Bauxite residue recovery includes mixing a solution of hydrochloric acid (HCL) according to a predetermined concentration, and adding the HCL solution to a quantity of raw red mud recovered from industrial operations as waste material. The highly alkaline property of the bauxite residue, commonly known as red mud is at least partially neutralized from the HCL, and makes the resulting washed red mud more amenable to subsequent uses in various applications in fields such as construction, wastewater treatment, and metal recovery processes. The process recovers washed red mud from the red mud and HCL solution by filtering the raw red mud and HCL solution for generating a stream of leach liquor from the filtrate and the recovered washed red mud from the residue. The neutralized red mud is further treated to extract metals such as calcium, iron, aluminum, silicon, and titanium.

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 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 preparing high purity alumina (HPA) is provided. The method includes subjecting an aluminum feedstock to acid leaching, thereby yielding an aluminum bearing leachate; subjecting the aluminum bearing leachate to solvent extraction, thereby yielding an organic phase which is loaded with aluminum; stripping the aluminum from the loaded organic phase with a stripping solution containing an acid, thereby yielding an aluminum bearing extract; crystallizing an aluminum salt from the aluminum bearing extract; dissolving the aluminum salt in an ammoniacal solution, thereby generating a boehmite precursor compound and an ammonium salt; calcining the boehmite precursor compound to yield HPA; subjecting the ammonium salt to electro-dialysis, thereby yielding ammonia and the acid; and performing at least one step of (a) utilizing the ammonia in preparing the ammoniacal solution used in a subsequent iteration of the method, or (b) utilizing the acid in preparing the stripping solution used in a subsequent iteration of the method.

A method for preparing high purity alumina (HPA) is provided. The method includes subjecting an aluminum feedstock to acid leaching, thereby yielding an aluminum bearing leachate; subjecting the aluminum bearing leachate to solvent extraction, thereby yielding an organic phase which is loaded with aluminum; stripping the aluminum from the loaded organic phase with a stripping solution containing an acid, thereby yielding an aluminum bearing extract; crystallizing an aluminum salt from the aluminum bearing extract; dissolving the aluminum salt in an ammoniacal solution, thereby generating a boehmite precursor compound and an ammonium salt; calcining the boehmite precursor compound to yield HPA; subjecting the ammonium salt to electro-dialysis, thereby yielding ammonia and the acid; and performing at least one step of (a) utilizing the ammonia in preparing the ammoniacal solution used in a subsequent iteration of the method, or (b) utilizing the acid in preparing the stripping solution used in a subsequent iteration of the method.

Disclosed are methods for preparing high-purity boehmite and porous gamma-alumina nano-powder, comprising: adding aluminum isopropoxide into water and stirring the aluminum isopropoxide added water, then adding aluminum hydroxide generated by hydrolysis of high-purity aluminum powder into that stirred water, stirring that aluminum hydroxide added water to obtain a mixed system; carrying out hydrothermal reaction on the mixed system, performing centrifuging, washing, drying and crushing to the reacted mixed system, obtaining high-purity boehmite; calcining the high-purity boehmite to obtain porous gamma (γ)-alumina nano-powder. By strictly controlling the addition of isopropanolic aluminum and the temperature as well as the duration of the hydrothermal reaction, the product boehmite γ-AlOOH obtains good character in terms of crystalline structure, purity, morphology and dispersion; γ-Al.sub.2O.sub.3 obtained after calcining remains basically the same morphology as that of boehmite powder with good powder dispersion and no major changes.

Disclosed are methods for preparing high-purity boehmite and porous gamma-alumina nano-powder, comprising: adding aluminum isopropoxide into water and stirring the aluminum isopropoxide added water, then adding aluminum hydroxide generated by hydrolysis of high-purity aluminum powder into that stirred water, stirring that aluminum hydroxide added water to obtain a mixed system; carrying out hydrothermal reaction on the mixed system, performing centrifuging, washing, drying and crushing to the reacted mixed system, obtaining high-purity boehmite; calcining the high-purity boehmite to obtain porous gamma (γ)-alumina nano-powder. By strictly controlling the addition of isopropanolic aluminum and the temperature as well as the duration of the hydrothermal reaction, the product boehmite γ-AlOOH obtains good character in terms of crystalline structure, purity, morphology and dispersion; γ-Al.sub.2O.sub.3 obtained after calcining remains basically the same morphology as that of boehmite powder with good powder dispersion and no major changes.

The present invention relates to an alumina with a particular pore profile and good thermal stability. This alumina is also characterized in that it has a high bulk density. The alumina has, after calcining in air at 1100° C. for 5 hours: a pore volume in the range of pores with a size of between 5 nm and 100 nm which is between 0.50 and 0.75 mL/g, more particularly between 0.50 and 0.70 mL/g; and a pore volume in the range of pores with a size of between 100 nm and 1000 nm which is less than or equal to 0.20 mL/g, more particularly less than or equal to 0.15 mL/g, or even less than or equal to 0.10 mL/g.

The present invention relates to an alumina with a particular pore profile and good thermal stability. This alumina is also characterized in that it has a high bulk density. The alumina has, after calcining in air at 1100° C. for 5 hours: a pore volume in the range of pores with a size of between 5 nm and 100 nm which is between 0.50 and 0.75 mL/g, more particularly between 0.50 and 0.70 mL/g; and a pore volume in the range of pores with a size of between 100 nm and 1000 nm which is less than or equal to 0.20 mL/g, more particularly less than or equal to 0.15 mL/g, or even less than or equal to 0.10 mL/g.

A microsphere of oxide has an opening on its surface connected to a hollow core inside, forming a cavity. The oxide the microsphere is made of is selected from the group consisting of alumina, silica, zirconia, magnesium oxide, calcium oxide and titania. The microsphere of oxide shows better mass and heat transfer characteristics, and has strength significantly higher than that of existing products with similar structures. A FT synthesis catalyst has the microsphere of oxide as a support and an active metal component disposed on the support. The active metal component is one or more selected from the group consisting of Co, Fe, and Ru.