Abstract: Corrosion-inhibiting pigments based on cobalt are described that contain a trivalent or tetravalent cobalt/valence stabilizer complex. An inorganic or organic material is used to stabilize the trivalent or tetravalent cobalt ion to form a compound that is sparingly soluble in water. Specific stabilizers are chosen to control the release rate of trivalent or tetravalent cobalt during exposure to water and to tailor the compatibility of the powder when used as a pigment in a chosen binder system. Stabilizers may also modify the processing and handling characteristics of the formed powders. Cobalt/valence stabilizer combinations are chosen based on the well-founded principles of cobalt coordination chemistry. Many cobalt-valence stabilizer combinations are presented that can equal the performance of conventional hexavalent chromium systems.

Abstract: Corrosion-inhibiting pigments based on cobalt are described that contain a trivalent or tetravalent cobalt/valence stabilizer complex. An inorganic or organic material is used to stabilize the trivalent or tetravalent cobalt ion to form a compound that is sparingly soluble in water. Specific stabilizers are chosen to control the release rate of trivalent or tetravalent cobalt during exposure to water and to tailor the compatibility of the powder when used as a pigment in a chosen binder system. Stabilizers may also modify the processing and handling characteristics of the formed powders. Cobalt/valence stabilizer combinations are chosen based on the well-founded principles of cobalt coordination chemistry. Many cobalt-valence stabilizer combinations are presented that can equal the performance of conventional hexavalent chromium systems.

Abstract: Rinsing or sealing solutions comprising a rare earth element and a valence stabilizer for barrier films. The treated films contain a rare earth/valence stabilizer complex. The rare earth element is selected from cerium, praseodymium, terbium, or combinations thereof, and at least one rare earth element is in the tetravalent oxidation state. The rinsing or sealing solution may also contain an optional preparative or solubility control agent. The oxidized rare earth element is present in the coating in a “sparingly soluble” form. The valence stabilizers can be either inorganic or organic in nature. A number of rare earth/valence stabilizer combinations that match the performance of conventional hexavalent chromium systems are presented.

Abstract: Conversion coatings comprising a rare earth element and a valence stabilizer combined to form a rare earth/valence stabilizer complex are described for substrate metals. The rare earth element is selected from cerium, praseodymium, terbium, or combinations thereof, and at least one rare earth element is in the tetravalent oxidation state. The coating bath may also contain a preparative or solubility control agent. The oxidized cerium, praseodymium or terbium is present in the coating in a “sparingly soluble” form. The valence stabilizers can be either inorganic or organic in nature. A number of cerium, praseodymium, or terbium/valence stabilizer combinations are presented that can equal the performance of conventional hexavalent chromium systems.

Abstract: Conversion coatings based on cobalt are described for substrate metals such as aluminum, zinc, magnesium, titanium, cadmium, silver, copper, tin, lead, cobalt, zirconium, beryllium, or indium, their alloys, or items coated with these metals. The conversion coating contains a trivalent or tetravalent cobalt/valence stabilizer complex. The coating bath may also contain a preparative agent or solubility control agent. The oxidized cobalt is present in the coating in a “sparingly soluble” form. The valence stabilizers can be either inorganic or organic in nature. Cobalt/valence stabilizer combinations are chosen based on the well-founded principles of cobalt coordination chemistry. A number of cobalt/valence stabilizer combinations that match the performance of conventional hexavalent chromium systems are presented.

Abstract: A corrosion-inhibiting pigment comprising a rare earth element and a valence stabilizer combinded to form a rare earth/valence stabilizer complex. The rare earth element is selected from cerium, terbium, praseodymium, or a combination thereof, and at least one rare earth element is in the tetravalent oxidation state. An inorganic or organic material is used to stabilize the tetravalent rare earth ion to form a compound that is sparingly soluble in water. Specific stabilizers are chosen to control the release rate of tetravalent cerium, terbium, or praseodymium during exposure to water and to tailor the compatibility of the powder when used as a pigment in a chosen binder system. Stabilizers may also modify the processing and handling characteristics of the formed powders. Many rare earth-valence stabilizer combinations are presented that can equal the performance of conventional hexavalent chromium systems.

Abstract: Rinsing or sealing solutions based on cobalt are described for barrier films such as anodic coatings, phosphate coatings, or “black oxide” coatings. The treated films contain a trivalent or tetravalent cobalt/valence stabilizer complex. The rinsing or sealing bath may also contain an optional preparative agent or an optional solubility control agent. The oxidized cobalt is present in the coating in a “sparingly soluble” form. The valence stabilizers can be either inorganic or organic in nature. Cobalt/valence stabilizer combinations are chosen based on the well-founded principles of cobalt coordination chemistry. A number of cobalt/valence stabilizer combinations that match the performance of conventional hexavalent chromium systems are presented.

Abstract: A process for recovery of hexavalent chromium from waste streams. The method includes providing a waste stream containing hexavalent chromium, reacting a soluble non-toxic precipitating reagent with the hexavalent chromium to form an insoluble precipitating reagent-chromate precipitate, and recovering the insoluble precipitating reagent-chromate precipitate. It may optionally include reacting the insoluble precipitating reagent-chromate precipitate with an acidic solution to form an insoluble precipitating reagent precipitate and a soluble hexavalent chromium compound, and recovering the soluble hexavalent chromium compound. The process may also include reacting the insoluble precipitating reagent precipitate with a solubilizing reagent to form the soluble non-toxic precipitating reagent.

Abstract: A corrosion-inhibiting pigment comprising a rare earth element and a valence stabilizer combinded to form a rare earth/valence stabilizer complex. The rare earth element is selected from cerium, terbium, praseodymium, or a combination thereof, and at least one rare earth element is in the tetravalent oxidation state. An inorganic or organic material is used to stabilize the tetravalent rare earth ion to form a compound that is sparingly soluble in water. Specific stabilizers are chosen to control the release rate of tetravalent cerium, terbium, or praseodymium during exposure to water and to tailor the compatibility of the powder when used as a pigment in a chosen binder system. Stabilizers may also modify the processing and handling characteristics of the formed powders. Many rare earth-valence stabilizer combinations are presented that can equal the performance of conventional hexavalent chromium systems.

Abstract: Conversion coatings comprising a rare earth element and a valence stabilizer combined to form a rare earth/valence stabilizer complex are described for substrate metals. The rare earth element is selected from cerium, praseodymium, terbium, or combinations thereof, and at least one rare earth element is in the tetravalent oxidation state. The coating bath may also contain a preparative or solubility control agent. The oxidized cerium, praseodymium or terbium is present in the coating in a “sparingly soluble” form. The valence stabilizers can be either inorganic or organic in nature. A number of cerium, praseodymium, or terbium/valence stabilizer combinations are presented that can equal the performance of conventional hexavalent chromium systems.

Abstract: Rinsing or sealing solutions comprising a rare earth element and a valence stabilizer for barrier films. The treated films contain a rare earth/valence stabilizer complex. The rare earth element is selected from cerium, praseodymium, terbium, or combinations thereof, and at least one rare earth element is in the tetravalent oxidation state. The rinsing or sealing solution may also contain an optional preparative or solubility control agent. The oxidized rare earth element is present in the coating in a “sparingly soluble” form. The valence stabilizers can be either inorganic or organic in nature. A number of rare earth/valence stabilizer combinations that match the performance of conventional hexavalent chromium systems are presented.

Abstract: Conversion coatings based on cobalt are described for substrate metals such as aluminum, zinc, magnesium, titanium, cadmium, silver, copper, tin, lead, cobalt, zirconium, beryllium, or indium, their alloys, or items coated with these metals. The conversion coating contains a trivalent or tetravalent cobalt/valence stabilizer complex. The coating bath may also contain a preparative agent or solubility control agent. The oxidized cobalt is present in the coating in a “sparingly soluble” form. The valence stabilizers can be either inorganic or organic in nature. Cobalt/valence stabilizer combinations are chosen based on the well-founded principles of cobalt coordination chemistry. A number of cobalt/valence stabilizer combinations that match the performance of conventional hexavalent chromium systems are presented.

Abstract: Rinsing or sealing solutions based on cobalt are described for barrier films such as anodic coatings, phosphate coatings, or “black oxide” coatings. The treated films contain a trivalent or tetravalent cobalt/valence stabilizer complex. The rinsing or sealing bath may also contain an optional preparative agent or an optional solubility control agent. The oxidized cobalt is present in the coating in a “sparingly soluble” form. The valence stabilizers can be either inorganic or organic in nature. Cobalt/valence stabilizer combinations are chosen based on the well-founded principles of cobalt coordination chemistry. A number of cobalt/valence stabilizer combinations that match the performance of conventional hexavalent chromium systems are presented.

Abstract: A process for recovery of hexavalent chromium from waste streams. The method includes providing a waste stream containing hexavalent chromium, reacting a soluble non-toxic precipitating reagent with the hexavalent chromium to form an insoluble precipitating reagent-chromate precipitate, and recovering the insoluble precipitating reagent-chromate precipitate. It may optionally include reacting the insoluble precipitating reagent-chromate precipitate with an acidic solution to form an insoluble precipitating reagent precipitate and a soluble hexavalent chromium compound, and recovering the soluble hexavalent chromium compound. The process may also include reacting the insoluble precipitating reagent precipitate with a solubilizing reagent to form the soluble non-toxic precipitating reagent.

Abstract: The present invention is directed to an apparatus and method for recovering the group III elemental component of a group III-V material waste material. The method includes heating, under a reduced pressure, solid waste materials which contain group III-V material to cause the group III-V material to separate into a group III element and a group V element vapor; drawing off the group V element vapor; condensing the group V element vapor to produce a condensed group V element solid; and zone refining the group III element to produce a purified group III element. The apparatus is designed to carry out this method in the plant which manufactures the group III-V waste material.

Abstract: The present invention is directed to a method for separating the group III element component of a group III-V material from an aqueous waste containing a group III-V material to allow for their recovery and beneficial use. The method includes adjusting the pH of an aqueous waste containing a group III-V material to a pH from about 9.5 to about 12.5 by adding an alkali metal hydroxide base to the aqueous waste; precipitating a group V element oxyanion by adding a soluble alkaline metal salt to the aqueous waste; separating the group V element oxyanion from the aqueous waste; adjusting the pH of the aqueous waste to form a group III element hydroxide precipitate by adding a mineral acid to the aqueous waste; separating the group III element hydroxide precipitate from the aqueous waste; and recovering the group III element from the group III element hydroxide precipitate.