10 results about "Chromate and dichromate" patented technology

A method for determining the presence of chromium-6 (Cr-6) in a solid sample is described, comprising the steps of contacting the solid sample with a destruction liquid under conditions in which the Cr-6 of the solid sample dissolves in the destruction liquid as a chromate, providing a test solution; subjecting the test solution obtained in step (1) to a specific Cr-6 detection reaction, under conditions in which the presence of Cr-6 is detected; and detecting whether the specific Cr-6 reaction occurred in step (2); wherein the destruction liquid comprises an oxidant, which has a standard electrode potential E0 higher than the chromate.

The present invention relates to systems and methods for catalytic removal of oxidized contaminants (for example, nitrite, chromate, chlorate, trichloroethene, CFC-11, 4-nonylphenol, RDX, and perfluorooctanoate) from water and wastewater. In some aspects, the catalytic method of removing oxidized contaminants comprises using precious metal nanoparticles as catalysts to reduce the oxidized contaminants.

Disclosed is a method for determination of the presence chromium-6 (Cr-6) in a solid sample, comprising the steps of contacting the solid sample with a destruction liquid under conditions wherein Cr-6 from the solid sample dissolves in the destruction liquid as a chromate, providing a test solution; subjecting the test solution obtained in step (1) to a specific Cr-6 detection reaction, under conditions wherein the presence of Cr-6 is detected; and detecting whether the Cr-6 specific reaction occurred in step (2); wherein the destruction liquid comprises an oxidator, having a higher standard electrode potential E0 than the chromate.

This invention relates to an organic-inorganic hybrid passivation solution and method for zinc-aluminum-magnesium plating to resist blackening. It primarily aims to provide a novel, pollution-free passivation solution and treatment method for enhancing the anti-blackening and corrosion resistance of zinc-aluminum-magnesium products, belonging to the field of metal material surface treatment technology. The passivation solution contains a key component, an acrylic acid-phosphonic acid copolymer, which chelates with zinc, aluminum, and magnesium ions on the plating surface through phosphonic acid groups in its molecular chain, constructing a chemically bonded organic-inorganic hybrid network that significantly improves the adhesion and corrosion resistance of the passivation film. This copolymer remains stable under strongly acidic conditions with a pH of 1-3 and can form a film normally. The passivation solution of this invention is chromium-free, environmentally friendly and safe, and can be directly applied to continuous zinc plating production lines without a separate degreasing process, simplifying the process flow. Zinc-aluminum-magnesium plating treated with this invention exhibits excellent resistance to white rust and blackening in salt spray tests, effectively replacing traditional chromate passivation processes.

There is a metal pipe coated on at least a section of the metal pipe with a polyolefin coating system. The system has the following layers: (a) optionally, a corrosion protective layer of a chromate, phosphate or other salt; (b) a polyolefin based adhesive, preferably in a thickness of 0.3-5 mm; (c) a PE or PP coating layer, preferably in a thickness of 1-10 mm; and (d) optionally, an adhesion promoting layer between the polyolefin based adhesive and a PE or PP layer. The polyolefin based adhesive contains an organic phase having substantially saturated hydrocarbons. The adhesive has amorphous polypropylene, ethylene-propylene copolymers or poly(iso)butylene (co)polymers. The adhesive is flowable when a pressure of 10 kgf / cm2 is applied. The PE or PP coating is a continuous layer over the coated section. The polyolefin based adhesive adheres to both the metal pipe and to the PE or PP coating.

This utility model discloses a choke tuner with isolation circuit, relating to the field of tuner technology. It includes a tuner housing, a capacitor, a choke coil assembly, and a display screen. The capacitor is installed inside the tuner housing, and the choke coil assembly is disposed on one side of the capacitor. The display screen is fixedly embedded in the upper surface of the tuner housing. The corners of the tuner housing are chamfered. The capacitor has an electrical specification of 20uF / 1000V, and forms an LC resonant circuit through an inductor. The tuner housing is made of FV-2 flame-retardant material with insulation class F and high-temperature resistance class F, effectively preventing fire risks. The surface of the housing is treated with chromate passivation zinc plating to form an anti-oxidation colored film, enhancing corrosion resistance. The use of a 20μF / 1000V capacitor paired with a high-saturation-current inductor meets the requirements of high-current applications, improves energy transmission efficiency, and enhances the safety of the tuner.

This invention relates to the field of metal material corrosion and protection technology, and discloses a method for inhibiting Cl-containing corrosion. ‑ A method for corroding stainless steel in a high-temperature, concentrated alkaline environment, including a temperature of 150℃ and Cl... ‑ In an alkaline solution with an ion concentration of 3.5 g / L and a NaOH mass fraction of 50%, the addition of chromate additives to the system enables the formation / maintenance of a stable passivation film with chromium enrichment characteristics on the stainless steel surface. This reduces the dissolution and damage to the film layer by the solution and improves the film's density and stability. The passivation film structure remains effectively stable even under harsh conditions of strong alkali and high temperature, improving the corrosion resistance and long-term operational reliability of stainless steel. It is suitable for corrosion control in alkaline processes, alkaline solution circulation systems, and high-temperature alkaline media equipment.

The invention relates to a method and a device for recycling lithium bromide solutions containing chromate from cold absorption systems, wherein barium bromide is added to a lithium chromate-containing lithium bromide solution and the chromate to be removed is replaced by bromide, in that lithium bromide is directly produced from the lithium chromate according to the formula: Ba 2+ + 2 Br - + 2 Li + + CrO4 2- → BaCrO4 (s) + 2 Li + + 2 Br - is generated. The plant has at least one stirred tank (1), wherein the stirred tank has a common or separate feed for lithium chromate-containing lithium bromide solution, barium bromide and activated carbon, as well as an air supply, a vent and a stirrer, and a discharge for the reaction product from the tank.