9 results about "Sodium dichromate" patented technology

The invention discloses a chromic oxide powder preparation method and device, and belongs to the technical field of chromic oxide powder preparation. According to the method, anhydrous sodium dichromate and powdered sulfur are used as raw materials and are mixed according to a molar ratio, and the mixture and a ball-milling medium are placed in a ball-milling tank together. After an inert protective atmosphere is formed through vacuum pumping and argon replacement, a mechanochemical reaction is carried out under the action of a high-energy ball mill, and a mixture of chromic oxide, sodium sulfate and powdered sulfur is directly generated. And washing the reaction product with water to remove soluble sodium sulfate and sulfur powder, and drying to obtain the superfine chromic oxide powder. The method is simple in process, mild in reaction condition, low in energy consumption and environmentally friendly, and the prepared chromium oxide powder is high in purity and fine and uniform in particle size and has a good application prospect.

The application relates to the technical field of electroplating, and discloses a chromium electroplating process for improving the hardness of a connector terminal, which comprises the following steps: performing surface pretreatment on the connector terminal, removing surface impurities through ultrasonic cleaning and micro-etching treatment; performing heating treatment on the connector terminal; performing electroplating treatment on the connector terminal by using an electroplating solution comprising trivalent chromium salt, boron nitride nanoparticles, ferroferric oxide nanoparticles, nickel ions, sodium dichromate and chromium alloy additives, so as to form a chromium plating layer; performing passivation treatment on the plating layer; performing low-temperature treatment on the plating layer; and spraying a protective layer on the chromium plating layer. Through the trivalent chromium salt and the sodium dichromate, the trivalent chromium salt is used to reduce hexavalent chromium ions into trivalent chromium, the toxicity of the hexavalent chromium is reduced, the sodium dichromate is used to provide a stable chromium source, the deposition of chromium elements in the electroplating process is ensured, the pollution of hexavalent chromium to the environment and the harm of hexavalent chromium to the health of operators are solved, and the environmental protection and safety of the electroplating process are improved.

The invention discloses a method for extracting and converting bromine ions dissolved in a water body and detecting stable bromine isotopes, and belongs to the field of isotope detection methods. The method comprises the following steps: oxidizing bromide ions in a water body by using acidic sodium dichromate based on the oxidation-reduction characteristic of the bromide ions in the water body to obtain bromine gas, reacting the bromine gas with an alkaline solution to obtain sodium bromide, adding silver ions into the solution to generate silver bromide precipitates, drying the precipitates, quantitatively putting the precipitates into a jaw headspace bottle in a dark environment, and adding methyl iodide; reacting under optimized conditions to generate methyl bromide gas; a gas isotope mass spectrometer and a gas chromatograph which are provided with receiving cups with the mass numbers of 94 and 96 are used in a combined mode, interference of impurity gas is eliminated through modified Isolink II equipment, after bromomethane mixed gas is separated through a chromatographic column, the impurity gas is emptied, bromomethane enters the mass spectrometer, and the bromine isotope ratio is accurately measured. The method can be used for evaluating and researching sources, causes and formation hydrogeochemical and physical processes of oil field water, underground brine, salt water and the like.

The utility model discloses a kind of automatic impurity removal filter equipment in sodium dichromate continuous crystallization production, including filter box, the top of the filter box is connected with feed hopper, the bottom of the filter box is connected with discharge pipe, adjusting plate is inserted and connected and installed in the inside of the discharge pipe, the upper portion of the filter box inner chamber is installed with filter frame, the middle part of the filter frame is embedded and installed with coarse filter screen, the bottom of the coarse filter screen is installed with vibration motor.The utility model realizes two-stage filtration by setting coarse filter screen and fine filter plate, simultaneously, vibration motor is used to drive coarse filter screen vibration, driving motor is used to drive impact plate to make fine filter plate vibrate, effectively prevent filter material blockage, significantly improve the filtration speed and efficiency, meet the continuous production demand, two-stage filtration structure cooperates vibration cleaning function, can effectively intercept different particle size impurities, improve filtration precision, ensure the stability of sodium dichromate product quality.

The invention provides a preparation method of light-color rice bran wax acid wax, which comprises the following steps: deoiling: soaking deoiled and undecolorized rice bran wax in ethyl acetate, heating and melting, cooling and slicing for later use; oxidation: heating the sliced rice bran wax and dilute sulphuric acid to melt the rice bran wax, adding a sodium bichromate solution, continuously stirring until the color of the rice bran wax is changed from brown to light, naturally cooling, and standing to layer the wax and the chromium slurry solution; pickling and washing, heating the oxidized rice bran wax into liquid, adding dilute sulphuric acid, stirring, standing to layer the wax and the dilute sulphuric acid solution, adding water, stirring and heating until the wax is completely molten, continuously stirring and standing to layer the wax and the washing liquid, cooling the oxidized rice bran wax on the upper layer, slicing and packaging. The invention also provides the light rice bran wax acid wax. The rice bran wax is oxidized by sodium bichromate to generate the light-color, odorless and hard rice bran wax acid wax, small molecular substances are effectively removed, the emulsifying property and glossiness are obviously improved, and deep processing is facilitated.

This invention pertains to a process for repairing localized damage to the oxide film on cast magnesium parts, specifically a repair solution and method for this oxide film. The repair solution comprises magnesium oxide and sodium dichromate, with magnesium oxide content at 40-50 g / L and sodium dichromate content at 4-6 g / L. Using this repair solution, the oxide film forms rapidly with a thickness of 5-8 μm; it withstands neutral salt spray for 96 hours; and it has a uniform purplish-black color. Suitable for localized repair of both small and large parts, the preparation and operation method is simple and low-cost, the repair time is short, and the pass rate is high. It can be widely applied to the repair of locally damaged oxide films on cast magnesium parts in military, aerospace, shipbuilding, and civilian applications, with good results and without the need for part disassembly.

Methods and compositions for rapid verification of cleaning performance on surfaces in cleaning-in-place (CIP) systems and in cleaning-in-place (COP) systems and in high flow areas. The solution comprises alkali metal hydroxide; one or more oxidizing compounds, wherein the one or more oxidizing compounds comprise sodium hypochlorite, potassium hypochlorite, sodium persulfate, potassium persulfate and monopersulfate; and one or more compounds selected from the group consisting of potassium permanganate, sodium permanganate, potassium dichromate, and sodium dichromate. In some examples, the solution also includes potassium tripolyphosphate, sodium tripolyphosphate, or other tripolyphosphate. The substrate is in contact with the solution, and a chromogenic reaction may occur indicating the presence of an organic substance or non-organic contaminant. The chromogenic reaction may occur within less than 30 minutes and at a temperature of 10 DEG C to 60 DEG C.

The long-acting anticorrosive antibacterial hydrophilic coating aluminum foil comprises a base material layer and a hydrophilic antibacterial layer, the top surface of the base material layer is provided with a conversion layer, the top surface of the conversion layer is provided with an anticorrosive layer, and the hydrophilic antibacterial layer is arranged on the top surface of the anticorrosive layer. The base material layer is prepared from the following components in parts by weight: 800-900 parts of aluminum ingots, 10-15 parts of manganese ingots, 5-7 parts of iron ingots and 1-2 parts of copper ingots; the conversion layer is prepared from the following components in parts by weight: 1.5 to 4 parts of sodium dichromate, 0.5 to 1.5 parts of sodium fluoride, 0.1 to 0.5 part of wetting agent and deionized water; the long-acting corrosion-resistant antibacterial hydrophilic coating aluminum foil adopts a four-layer design of the base material layer, the conversion layer, the corrosion-resistant layer and the hydrophilic antibacterial layer, successfully integrates excellent long-acting corrosion resistance, lasting hydrophilicity and efficient broad-spectrum antibacterial property, and adopts an environment-friendly formula and a precise and controllable preparation process; the durability and heat exchange efficiency of the aluminum foil in the high-temperature and high-humidity environment are remarkably improved, energy consumption is effectively reduced, and the sanitation risk caused by microorganism breeding is eradicated.

The invention discloses a method for circularly and continuously neutralizing a carbonization solution in sodium chromate production, which comprises the following steps: adding the carbonization solution into a sodium chromate alkaline solution or slurry for continuous neutralization, and then washing with a filter to obtain a sodium chromate neutral solution and filter residues; adding a carbonization solution into the sodium chromate neutral solution for acidification pretreatment to obtain a pretreatment solution, evaporating the pretreatment solution, introducing CO2 for carbonization, filtering a carbonization product with a filter, and washing with hot water to obtain a carbonization solution and sodium bicarbonate; and adding the carbonized solution into a new sodium chromate alkaline solution or slurry, carrying out continuous neutralization and washing with a filter to obtain a sodium chromate neutral solution, and repeating the operation to realize cyclic continuous neutralization of the carbonized solution in sodium chromate production. The method is simple to operate, the generation of chromium-containing sodium sulfate in the existing sodium bichromate production process can be reduced, the environmental protection risk and the production cost are reduced, the produced by-product sodium bicarbonate returns to a calcium-free roasting system to replace part of sodium carbonate to participate in batching, and industrial green production is facilitated.