36 results about "Chromium Hexavalent Compound" patented technology

The present disclosure provides an identification process which may employ various identification techniques on Zero platinum group metal (ZPGM) catalyst systems, in order to identify responsible materials for the formation of corrosion material, such as hexavalent chromium compounds. Identification analysis, such as X-ray diffraction analysis (XRD), X-ray fluorescence (XRF), and X-ray Photoelectron Spectroscopy (XPS) may be performed on various thermally treated ZPGM catalyst systems, such as in bare substrate, substrate with one type of ZPGM in washcoat, a substrate with one type of ZPGM in overcoat and substrate combination of ZPGM metals in both washcoat and overcoat. Results of identification analysis may show that regardless of metal catalyst (for example Ag, Cu, Ce), hexavalent chromium (Cr⁶⁺) may be formed on aged catalysts systems, which may be due to the high concentration of chromium in substrate. Therefore, corrosion and production of hexavalent chromium may initiate from elements found in the substrate and not from elements within the ZPGM metal catalysts.

There are provided aluminum elements covered on their surfaces with a coating film free from harmful hexavalent chromium compounds and fluorine compounds. Particularly, aluminum dicast and aluminum cast materials having excellent paint adherence and corrosion resistance are provided. The coating film for aluminum elements comprises (i) chromium, (ii) zinc and (iii) cobalt and/or titanium with 95% by mass or more of said chromium being a trivalent chromium.

The present invention relates to a carbon nano hollow sphere and its preparation method. Said method includes: using chromic compound to oxidize and polymerize aniline to form polyaniline and chromic hydroxide co-mixed precipitate, washing and drying to obtain the chromic hydroxide co-mixed precipitate, washing and drying to obtain the chromic hydroxide nano composite powder covered by polyaniline, under the condition of isolating air heating the polyaniline/chromic hydroxide nano composite powder to high-temp., making carbonization treatment to obtain the composite powder whose chromic hydroxide nano granule surface is covered with carbon, then dissolving said composite powder in acidic solution to remove chromic hydroxide to obtain the carbon nano hollow sphere which has the structure similar to carbon nano tube, can be used as hydrogen storing material or negative material of lithium ion cell.

The present disclosure provides identification techniques on platinum group metal (PGM) and zero platinum group metal (ZPGM) catalyst systems, in order to identify responsible materials for the formation of corrosion products, such as hexavalent chromium compounds. Identification analyses, such as X-ray diffraction analysis (XRD) and X-ray fluorescence (XRF) may be performed on various thermally treated PGM and ZPGM catalyst systems. Results of identification analyses may show that for both PGM and ZPGM catalysts, hexavalent chromium (Cr⁶⁺) may be formed during thermal aging at range of 600C to 900C. This may be due to the high concentration of chromium in substrate alloys. Therefore, occurrence of corrosion and production of hexavalent chromium may initiate from elements found in the substrate and not from elements within the PGM and ZPGM catalysts. Additionally, tests regarding washcoat adhesion and back pressure performed on disclosed PGM and ZPGM catalyst systems show that presence of corrosion products does not affect the quality of ZPGM and PGM catalyst systems.

The object is to provide an etching liquid for a conductive polymer having excellent etching capability toward a conductive polymer, and a method for patterning a conductive polymer employing the etching liquid for a conductive polymer. The conductive etching liquid of the present invention is selected from the group consisting of (1) an etching liquid comprising greater than 0.5 wt % but no greater than 70 wt % of (NH₄)₂Ce(NO₃)₈ or at least 0.5 wt % but no greater than 30 wt % of Ce(SO₄)₂, (2) an etching liquid comprising greater than 0.5 wt % but no greater than 30 wt % of (NH₄)₄Ce(SO₄)₄, (3) an etching liquid comprising a hypochlorous acid salt aqueous solution having an effective chlorine concentration of at least 0.06 wt % and a pH of greater than 3 but less than 8, (4) an etching liquid comprising nitrosyl chloride which comprises at least 5 wt % of hydrochloric acid and at least 20 wt % of nitric acid, a (hydrochloric acid concentration+0.51×nitric acid concentration) value being no greater than 35 wt %, and a (hydrochloric acid concentration+0.5×nitric acid concentration) value being at least 30 wt %, (5) an etching liquid comprising at least 3 wt % but no greater than 40 wt % of a bromic acid compound and at least 4 wt % of an inorganic acid, (6) an etching liquid comprising at least 6 wt % but no greater than 40 wt % of a chloric acid compound and at least 7 wt % of a hydrogen halide, (7) an etching liquid comprising at least 0.001 wt % but no greater than 20 wt % of a permanganic acid compound, and (8) an etching liquid comprising at least 3 wt % but no greater than 30 wt % of a hexavalent chromium compound.

The present invention discloses a surface treatment method of a nickel metal strip for a lithium-ion battery negative electrode ear. The method includes two steps. A treatment liquid in a first step includes at least a hexavalent chromium compound, a fluorine compound, and a phosphorus compound. A treatment liquid in a second step includes at least organic acid, inorganic acid, and a fluorine compound. A chemical conversion film is formed by heating and drying after applying the treatment liquid on the surface of the nickel metal strip. The nickel metal strip treated by the method of the present invention after hot pressing with an ear adhesive has excellent electrolyte resistance property. The nickel metal strip is directly immersed in the electrolyte at 85 DEG C for 4.5 hours. The bonding strength is almost unchanged. Meanwhile, the nickel metal strip after treatment still has good soldering properties, and can be directly soldered on the surface thereof. The metal nickel strip is used for the production of lithium ion battery ears. The production process can be simplified. The cost is reduced.

The invention discloses a method for calcium-free calcination production of sodium chromate and chromium-containing cast iron as a co-product. The method comprises the following steps of 1, first-stage calcination by mixing chromite and soda ash according to a certain ratio to obtain a first-stage mixed material, wherein a soda ash use amount is 35-60% of the theoretical alkali use amount, putting the first-stage mixed material into a rotary kiln, carrying out oxidizing calcination, and carrying out impregnation and filtration of the calcined clinker to obtain a first-stage sodium chromate alkali solution and filter residues, and 2, treating the filter residues, and carrying out second-stage calcination and third-stage calcination of the filter residues by the step 1 to obtain second-stage calcination filter residues, third-stage calcination filter residues, a second-stage calcination sodium chromate alkali solution and a third-stage calcination sodium chromate alkali solution, wherein the third-stage calcination filter residues can be used for co-production of chromium-containing cast iron. The method does not adopt any auxiliary materials in calcination, and effectively avoids ring forming of the rotary furnace. The calcination residues obtained by the method does not contain hexavalent chromium compounds and thus chromium residue harmlessness and recycling are realized. Through co-production of high-carbon chromium iron, a chromium comprehensive use ratio is improved by more than 95%. Through smelting, produced electroslag does not contain hexavalent chromium so that thorough detoxification of chromium residues is realized.

The present invention relates to nano composite carbon/chromium trioxide powder and its preparation. Polyaniline is oxide with hexad chromium compound to form the mixture precipitate of polyaniline and chromium hydroxide; the mixture precipitate is washed and dried to obtain nano composite polyaniline/chromium hydroxide powder; and under air isolating condition, the nano composite polyaniline/chromium hydroxide powder is heated to high temperature to obtain the nano composite carbon/chromium trioxide powder with carbon coating the nano chromium trioxide particle. The nano composite carbon/chromium trioxide powder of the present invention has small particle size and raised use effect as antiwear additive and is suitable for large-scale production.

The invention discloses a chromium-free environment-friendly insulating coating for oriented silicon steel. The chromium-free environment-friendly insulating coating is prepared from the following components in percentage by mass: 1 to 7 percent of tungstate, 1 to 5 percent of titanyl sulfate, 25 to 50 percent of aqueous solution of dihydric phosphate, 25 to 50 percent of silica sol and 10 to 40 percent of deionized water, wherein the sum of mass percents is 100 percent, and the sum of the contents of the tungstate and the titanyl sulfate is 2 to 8 percent of total mass of the coating. After the oriented silicon steel is coated with the coating, baking, sintering and curing need to be performed in protective atmosphere such as N2 or Ar. The insulating coating disclosed by the invention does not contain hexavalent chromium compounds harmful to a human body and environment, and belongs to an environment-friendly product, and has the advantages of good insulating property, corrosion resistance, adhesive property, high temperature resistance and the like; in addition, an iron loss value of the oriented silicon steel can be reduced, and a coating layer does not get tacky after being placed in a room temperature environment for a long time.

The invention relates to a spray chrome oxide preparation method, belongs to the inorganic material preparation field, and especially relates to a spray chrome oxide preparation method through a hydrothermal process. The method is characterized in that an oxidant is a hexavalent chromium compound, a reductant is micro-molecular alcohol or aldehyde, and a surfactant is polyol or polyprotic acid; and the method comprises following steps: mixing the reductant, the oxidant, the surfactant and water according to a reductant/oxidant ratio of 1-5(mol/mol) and a surfactant/oxidant ratio of 0.001-0.5(mol/mol), reacting at a constant reaction temperature of 100-300DEG C under an initial hydrothermal condition for a reaction period below 120min, washing the obtained precipitate, drying, and calcining at 800-1200DEG C for a period below 2h to obtain spherical micrometer controlled-spray chrome oxide. The method has the advantages of simple technology, realization of the calcining period far lower than that of present patents, less energy consumption, and popularization deserving.

The invention discloses a method for reducing emission of heavy metal chromium in a burning process. The method comprises the following steps: injecting 1g/Nm<3> to 20g/Nm<3> of main adsorbent based on Fe or Mg into tail flue gas of a high temperature (800 to 1100 DEG C) of a burning apparatus, wherein the adsorbent is solid powder, and a particle size of the adsorbent is 5 to 100 micrometers. Byvirtue of the chemical reaction and physical adsorption effect, Cr in the flue gas is adsorbed and can be converted into solid particles with an aerodynamic size being greater than 2.5 micrometers atthe high temperature, so that the Cr can be easily removed by a dust removal apparatus, and the generation of highly-toxic hexavalent chromium compounds in the ash can be inhibited. Gaseous toxic andharmful substances are converted to large-particle solids insoluble in water, so that the capturing and harmless and recycling treatment can be facilitated.

The invention discloses a method for extracting hexavalent chromium from a polymer. Organic solvents such as acetone and tetrahydrofuran are selected and used to fully dissolve the polymer; a sodium hydroxide or potassium hydroxide aqueous solution with a mass fraction of 0.5 percent to 10 percent is added to the polymer, is fully mixed with the polymer and then stand still until layering, and a lower layer aqueous solution is taken out; a sodium hydroxide or potassium hydroxide aqueous solution with a mass fraction of 0.5 percent to 10 percent is re-added into an upper layer organic solution, is fully mixed with the upper layer organic solution and stands still until layering, and a lower layer aqueous solution is re-taken out; and an aqueous solution fully extracting soluble hexavalent chromium and insoluble hexavalent chromium can be obtained only by combining the two lower layer aqueous solutions. The method has the following beneficial effects that: firstly, by adopting the method, the soluble hexavalent chromium and the insoluble hexavalent chromium in a polymer material can be fully extracted; secondly, mutual transformation of chromium valence states in the original compound cannot be caused when the soluble hexavalent chromium and the insoluble hexavalent chromium are extracted by adopting the method; and thirdly, the method has the characteristic that the operation is simple.

A coating composition is disclosed that includes a binder, a tri-valent chromium solid, and a stabilized oxidizing agent. The coating composition is used in a method to protect a surface of a metallic article, such as an aluminum article. The tri-valent chromium solid forms a soluble hexavalent chromium compound as a result of reaction with the oxidizing agent when activated in the presence of a corrosive environment. The released water soluble hexavalent chromium migrates to coating defects to protect the metallic article.

The invention discloses a method for completely extracting soluble hexavalent chromium from polymers and keeping valence states of chromium in original compounds unchanged. Firstly, tetrahydrofuran or acetone soluble polymers of organic solvents are used; and secondly, saturated inorganic salt solution is used for re-extracting the hexavalent chromium twice to combine a water layer. The method has the remarkable advantages that (1) the method can be used for completely extracting the soluble hexavalent chromium from polymer materials; (2) the method avoids mutual transformation of the valence states of the chromium in the original compounds while extracting the soluble hexavalent chromium, and is beneficial to detection of the content of the hexavalent chromium; and (3) the method is simple in operation.

The invention discloses a ray irradiating method to reduce chromic ion valent state in the food in the irradiating manufacturing domain, which is characterized by the following: the positive hexavalent chromium compounds are applied widely in the industry, which is easy to pollute; the method reduces natural background value to reduce harm for human and animal, which avoids skin cancer and lung carcinoma.

The invention belongs to the field of inorganic material preparation and especially relates to a method for preparing sprayed chrome oxide by a surfactant-free hydrothermal method. The method is characterized in that a used oxidizing agent is a metal cation-containing hexavalent chromium compound and a used reducing agent is small molecular alcohol or aldehyde, the reducing agent, the oxidizing agent and water are blended according to oxidizing agent concentration of 40g/l or more and a mole ratio of the reducing agent to the oxidizing agent of 0.2-5, then the reaction system undergoes a reaction at a constant reaction temperature of 140-300 DEG C under hydrothermal conditions for some time and generally for less than 120min, and the precipitates are washed, dried and calcined to form spherical micron-sized sprayed chrome oxide, wherein a calcining temperature is generally in a range of 800-1200 DEG C and calcining time is generally less than 2h. The method has simple processes, is superior to the prior art, and has low energy consumption and a good popularization value.

The invention discloses a three-dimensional layered chromium hydroxide monohydrate nanosphere and a preparation method thereof. The preparation method comprises the following steps: preparing a neutral or alkaline aqueous solution containing a hexavalent chromium compound and a reducing agent as a reaction solution, carrying out a hydrothermal reaction on the reaction solution at 200-280 DEG C, and carrying out post-treatment to obtain the three-dimensional layered chromium hydroxide monohydrate nanospheres. The three-dimensional layered chromium hydroxide monohydrate nanosphere has a unique microstructure, controllable size and strong acid and alkali resistance, has a large specific surface area and abundant surface hydroxyl groups, has the advantages of good dispersibility, high stability, good filtration performance and the like, has a wide application prospect, is simple in preparation process and easy to implement, and is suitable for industrial production. The cost is low, the controllability is good, and the requirements of industrial production can be well met.

The invention discloses nano chromium sesquioxide and a preparation method thereof. The preparation method comprises the following steps: preparing a neutral or alkaline aqueous solution containing a hexavalent chromium compound and a reducing agent as a reaction solution, carrying out a hydrothermal reaction on the reaction solution at 200-280 DEG C, and carrying out post-treatment to obtain the three-dimensional layered chromium hydroxide monohydrate nanospheres, and the three-dimensional layered chromium hydroxide monohydrate nanospheres are roasted at the temperature of 800 DEG C to 1000 DEG C, and the nano chromium sesquioxide is obtained. Compared with the prior art, the preparation process of the nano chromium sesquioxide is simple and controllable, chromium loss can be effectively avoided, no chromium-containing waste residue is discharged, the obtained nano chromium sesquioxide is uniform and controllable in particle size and morphology, and the nano chromium sesquioxide has wide application prospects in multiple fields, such as preparation of high-end pigments, grinding materials and the like.