Methods and compositions for improving performance of flocculants in an industrial production process. Methods include pH triggered cross-linking reaction between a flocculating agent, such as dextran, and a composition comprising a boronic acid-containing polymer. The pH trigger can be provided by a fluid having a pH of 8 or more. The production process can be a Bayer Process and the fluid is caustic liquor or slurry in the fluid circuit of the Bayer, wherein the reaction time is reduced over conventional methods and the cross-linked dextran composition effectuates improved flocculation of the trihydrate particles.

This invention relates to treated geothermal brine compositions containing reduced concentrations of lithium, iron and silica compared to the untreated brines. Exemplary compositions contain concentration of lithium ranges from 0 to 200 mg/kg, concentration of silica ranges from 0 to 30 mg/kg, concentration of iron ranges from 0 to 300 mg/kg. Exemplary compositions also contain reduced concentrations of elements like arsenic, barium, and lead.

This invention relates to treated geothermal brine compositions containing reduced concentrations of lithium, iron and silica compared to the untreated brines. Exemplary compositions contain concentration of lithium ranges from 0 to 200 mg/kg, concentration of silica ranges from 0 to 30 mg/kg, concentration of iron ranges from 0 to 300 mg/kg. Exemplary compositions also contain reduced concentrations of elements like arsenic, barium, and lead.

A method for recovery of aluminum hydroxide Al(OH).sub.3 from an aluminum enriched water/wastewater treatment sludge is disclosed. The method includes the steps of: adding a hydrated lime slurry to the aluminum enriched water/wastewater treatment sludge to form an alkaline sludge; adding sodium carbonate Na.sub.2CO.sub.3 to the alkaline sludge to form a Na.sub.2CO.sub.3 treated sludge; forming a first supernatant from the Na.sub.2CO.sub.3 treated sludge of step b) containing NaAl(OH).sub.4; introducing CO.sub.2 to the first supernatant to form a precipitate of Al(OH).sub.3 and a second supernatant containing NaHCO.sub.3; and recycling at least a portion of the NaHCO.sub.3 from the second supernatant back to the alkaline sludge of step a).

A method for recovery of aluminum hydroxide Al(OH).sub.3 from an aluminum enriched water/wastewater treatment sludge is disclosed. The method includes the steps of: adding a hydrated lime slurry to the aluminum enriched water/wastewater treatment sludge to form an alkaline sludge; adding sodium carbonate Na.sub.2CO.sub.3 to the alkaline sludge to form a Na.sub.2CO.sub.3 treated sludge; forming a first supernatant from the Na.sub.2CO.sub.3 treated sludge of step b) containing NaAl(OH).sub.4; introducing CO.sub.2 to the first supernatant to form a precipitate of Al(OH).sub.3 and a second supernatant containing NaHCO.sub.3; and recycling at least a portion of the NaHCO.sub.3 from the second supernatant back to the alkaline sludge of step a).

A method for recovery of aluminum hydroxide Al(OH).sub.3 from an aluminum enriched water/wastewater treatment sludge is disclosed. The method includes the steps of: adding a hydrated lime slurry to the aluminum enriched water/wastewater treatment sludge to form an alkaline sludge; adding sodium carbonate Na.sub.2CO.sub.3 to the alkaline sludge to form a Na.sub.2CO.sub.3 treated sludge; forming a first supernatant from the Na.sub.2CO.sub.3 treated sludge of step b) containing NaAl(OH).sub.4; introducing CO.sub.2 to the first supernatant to form a precipitate of Al(OH).sub.3 and a second supernatant containing NaHCO.sub.3; and recycling at least a portion of the NaHCO.sub.3 from the second supernatant back to the alkaline sludge of step a).

A method for recovery of aluminum hydroxide Al(OH).sub.3 from an aluminum enriched water/wastewater treatment sludge is disclosed. The method includes the steps of: adding a hydrated lime slurry to the aluminum enriched water/wastewater treatment sludge to form an alkaline sludge; adding sodium carbonate Na.sub.2CO.sub.3 to the alkaline sludge to form a Na.sub.2CO.sub.3 treated sludge; forming a first supernatant from the Na.sub.2CO.sub.3 treated sludge of step b) containing NaAl(OH).sub.4; introducing CO.sub.2 to the first supernatant to form a precipitate of Al(OH).sub.3 and a second supernatant containing NaHCO.sub.3; and recycling at least a portion of the NaHCO.sub.3 from the second supernatant back to the alkaline sludge of step a).

A method for manufacturing high-purity aluminum hydroxide and alumina material is disclosed, which includes the steps of: reacting aluminum metal with a mixture of organic base and water to form aluminum hydroxide suspension; removing water by filtration to form aluminum hydroxide slurry, and for manufacturing alumina material, further drying/baking the slurry to form aluminum oxide powders. The method is amenable to mass production of high-purity aluminum hydroxide and aluminum oxide containing total silica and non-aluminum metal impurities less than 0.005% and having a bulk density higher than 3.0 g/cc. In addition, the invention also provides high-purity aluminum hydroxide and aluminum oxide prepared by using the method disclosed and bulk products prepared therefrom.

A method for manufacturing high-purity aluminum hydroxide and alumina material is disclosed, which includes the steps of: reacting aluminum metal with a mixture of organic base and water to form aluminum hydroxide suspension; removing water by filtration to form aluminum hydroxide slurry, and for manufacturing alumina material, further drying/baking the slurry to form aluminum oxide powders. The method is amenable to mass production of high-purity aluminum hydroxide and aluminum oxide containing total silica and non-aluminum metal impurities less than 0.005% and having a bulk density higher than 3.0 g/cc. In addition, the invention also provides high-purity aluminum hydroxide and aluminum oxide prepared by using the method disclosed and bulk products prepared therefrom.

A process for recovery of all or some abrasive elements contained in an abrasive material in which the abrasive elements are dispersed in a resin with at least one phenolic hydroxyl group, the process including steps of: a) bringing the abrasive material into contact with an aqueous nitric solution (S.sub.1), whereby an aqueous nitric solution (S.sub.2) is obtained containing abrasive elements and residue derived from degradation of the resin; then (b) separating the abrasive elements from the aqueous nitric solution (S.sub.2) obtained after step (a). The use of abrasive elements thus recovered particularly to prepare agglomerated abrasives or coated abrasives.