The present invention discloses a method for aluminum-enhanced dealkalization of red mud and separation and recovery of aluminum and iron. The method includes: dissolving red mud in water, introducing excessive SO.sub.2, introducing O.sub.2 for aeration, and refluxing part of alkaline leachate after filtering; when pH of a red mud mixture decreases to below 3, washing and filtering the red mud mixture, adding NaOH to acidic leachate to adjust its pH to a strongly alkaline level, aging and filtering the leachate, treating filter residue to recover Fe.sub.2O.sub.3, and refluxing part of alkaline leachate after filtering to the red mud mixture; and adjusting pH of the remaining alkaline leachate after filtering to a weakly acidic level, and conducting filtering to recover aluminum.

A method for producing high purity iron oxide nanoparticles using nanoparticle-producing cells, including: a) a pre-growth step that includes amplifying the nanoparticle-producing cell(s) in a pre-growth and/or fed-batch medium/media, and b) a growth step that includes amplifying the nanoparticle-producing cell(s) originating from the pre-growth step in a growth and/or fed-batch medium/media, wherein the pre-growth and/or growth and/or fed-batch medium/media comprise(s), per kilogram or liter of pre-growth and/or growth and/or fed-batch medium/media: i) no more than 0.005 gram of yeast extract, and ii) no more than 0.001 gram of CMR agent selected from boric acid and nitrilotriacetic acid, wherein the fed-batch medium when it is present is a medium that supplements the pre-growth and/or growth medium/media, and wherein more nanoparticles are produced in the growth step than in the pre-growth step.

A dry reforming catalyst that includes treated black powder (primarily hematite), and a method of treating black powder (e.g., from a natural gas pipeline) to give the treated black powder. A dry reformer having the treated black powder as reforming catalyst, and a method of producing syngas with the dry reformer.

A dry reforming catalyst that includes treated black powder (primarily hematite), and a method of treating black powder (e.g., from a natural gas pipeline) to give the treated black powder. A dry reformer having the treated black powder as reforming catalyst, and a method of producing syngas with the dry reformer.

The present invention relates to novel processes for recovering iron values from the bauxite residue. It comprises drying the red mud either directly or after neutralizing or after water washing. The bauxite residue was treated with iron nanoparticles of varying the size from 100-1000 nm, heating in muffle furnace or inductive furnace at the temperature 700-800° C. The invention resulted in increasing in magnetic properties of a selected species by coating of the iron particles on their surfaces. The iron oxides Fe.sub.2O.sub.3 and α-FeOOH (goethite) present in the bauxite residue was converted to Fe.sub.3O.sub.4 (magnetite) after the treatment using inductive heating. Hence, magnetic susceptibility of the particles enhances and can be separated by magnetic separator and ultimately separated from the nonmagnetic material. Furthermore, the isolated iron enriched material was used for various applications such as reduction of arsenic, chemical oxygen demand (COD) in wastewater.

There is provided a method for manufacturing a soft magnetic member where a coating formed of an α-Fe.sub.2O.sub.3 single phase having a high electrical resistivity is formed on a soft magnetic alloy substrate. A soft magnetic alloy substrate is heated in an atmosphere containing water vapor and inert gas to form a coating on the soft magnetic alloy substrate. The atmosphere has an oxygen partial pressure in a range of 0 to 1.5 kPa. A soft magnetic member including the soft magnetic alloy substrate and the coating formed on its surface can be obtained.

There is provided a method for manufacturing a soft magnetic member where a coating formed of an α-Fe.sub.2O.sub.3 single phase having a high electrical resistivity is formed on a soft magnetic alloy substrate. A soft magnetic alloy substrate is heated in an atmosphere containing water vapor and inert gas to form a coating on the soft magnetic alloy substrate. The atmosphere has an oxygen partial pressure in a range of 0 to 1.5 kPa. A soft magnetic member including the soft magnetic alloy substrate and the coating formed on its surface can be obtained.

Magnetic powder includes: an epsilon-phase iron oxide-based compound selected from ε-Fe.sub.2O.sub.3 or a compound represented by Formula (1). The magnetic powder has an average particle diameter of 8 nm to 25 nm, a ratio of Hc to Hc′ of from 0.6 to 1.0, and Hc′ satisfying Expression (II). Hc′ represents a magnetic field at which a value of Expression (I) becomes zero in a magnetic field-magnetization curve obtained by performing measurement at a maximum applied magnetic field of 359 kA/m, a temperature of 296 K, and a magnetic field sweeping speed of 1.994 kA/m/s. M represents magnetization and H represents applied magnetic field. Hc represents a magnetic field at which magnetization becomes zero in the magnetic field-magnetization curve. In Formula (1), A represents at least one metal element other than Fe, and a represents a number that satisfies a relationship of 0<a<2.
d.sup.2M/dH.sup.2  Expression (I)
119 kA/m<Hc′<2380 kA/m  Expression (II)
ε-A.sub.aFe.sub.2-aO.sub.3  (1)

A process disclosed herein is related to the isolation and purification of substantially pure chemicals, including silica gel, sodium silicate, aluminum silicate, iron oxide, and rare earth elements (or rare earth metals, REEs), from massive industrial waste coal ash. In one embodiment, the process includes a plurality of caustic extractions of coal ash at an elevated temperature, followed by an acidic treatment to dissolve aluminum silicate and REEs. The dissolved aluminum silicate is precipitated out by pH adjustment as a solid product while REEs remain in the solution. REEs are captured and enriched using an ion exchange column. Alternatively, the solution containing aluminum silicate and REEs is heated to produce silica gel, which is easily separated from the enriched REEs solution. REEs are then isolated and purified from the enriched solution to afford substantially pure individual REE by a ligand-assisted chromatography. Additionally, a simplified process using one caustic extraction and one acidic extraction with an ion exchange process was also investigated and optimized to afford a comparable efficiency.

A process disclosed herein is related to the isolation and purification of substantially pure chemicals, including silica gel, sodium silicate, aluminum silicate, iron oxide, and rare earth elements (or rare earth metals, REEs), from massive industrial waste coal ash. In one embodiment, the process includes a plurality of caustic extractions of coal ash at an elevated temperature, followed by an acidic treatment to dissolve aluminum silicate and REEs. The dissolved aluminum silicate is precipitated out by pH adjustment as a solid product while REEs remain in the solution. REEs are captured and enriched using an ion exchange column. Alternatively, the solution containing aluminum silicate and REEs is heated to produce silica gel, which is easily separated from the enriched REEs solution. REEs are then isolated and purified from the enriched solution to afford substantially pure individual REE by a ligand-assisted chromatography. Additionally, a simplified process using one caustic extraction and one acidic extraction with an ion exchange process was also investigated and optimized to afford a comparable efficiency.