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.

A metal oxide powder in which the metal is other than uranium, iron and titanium, and, in the metal oxide powder, the content rate of uranium is 1.0 ppb by mass or less, the content rate of iron is 100 ppm by mass or less in terms of Fe.sub.2O.sub.3, the content rate of titanium in terms of TiO.sub.2 oxide is 8 ppm by mass or less. Included is a method of producing a metal oxide powder which removes impurities from a metal oxide powder so that a metal oxide powder having a high purity can be obtained, and a metal oxide powder produced according to the method.

A metal oxide powder in which the metal is other than uranium, iron and titanium, and, in the metal oxide powder, the content rate of uranium is 1.0 ppb by mass or less, the content rate of iron is 100 ppm by mass or less in terms of Fe.sub.2O.sub.3, the content rate of titanium in terms of TiO.sub.2 oxide is 8 ppm by mass or less. Included is a method of producing a metal oxide powder which removes impurities from a metal oxide powder so that a metal oxide powder having a high purity can be obtained, and a metal oxide powder produced according to the method.

Digestion of impure alumina with sulfuric acid dissolves all constituents except silica. The resulting sulfatesaluminum sulfate, ferric sulfate, titanyl sulfate, and magnesium sulfate for alumina contaminated with iron-, titanium-, and/or magnesium-containing speciesremain in solution at approximately 90 C. Hot filtration separates silica. Solution flow over metallic 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 remaining iron rich liquor also contains magnesium sulfate. The addition of oxalic acid generates insoluble ferrous oxalate which is thermally decomposed 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.

Digestion of impure alumina with sulfuric acid dissolves all constituents except silica. The resulting sulfatesaluminum sulfate, ferric sulfate, titanyl sulfate, and magnesium sulfate for alumina contaminated with iron-, titanium-, and/or magnesium-containing speciesremain in solution at approximately 90 C. Hot filtration separates silica. Solution flow over metallic 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 remaining iron rich liquor also contains magnesium sulfate. The addition of oxalic acid generates insoluble ferrous oxalate which is thermally decomposed 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.

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.

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.

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.