24 results about "Sodium dichromate" patented technology

The present invention provides a method for producing a molybdenum-vanadium-aluminum-chromium alloy with high uniformity. The composition of the molybdenum-vanadium-aluminum-chromium alloy is as follows: Mo 25% - 28%, V 24% - 27%, Cr 28% - 31%, with the balance being Al, O ≤ 0.05%, C ≤ 0.05%, and the segregation of the main content being < 0.6%. It relates to the field of metallurgical technology. The technological steps are as follows: (1) Prepare an ammonium molybdate-ammonium dichromate-ammonium metavanadate precursor by hydrothermal method using sodium molybdate, sodium metavanadate, sodium dichromate, and ammonium chloride; (2) Perform high-temperature treatment on the precursor to obtain a MoO3 / V2O5 / CrO3 composite material; (3) Mix the MoO3 / V2O5 / CrO3 composite material, refined aluminum powder, and calcium oxide in proportion, load them into a furnace and ignite to undergo a thermite reaction to obtain a molybdenum-vanadium-aluminum-chromium alloy ingot. Compared with the molybdenum-vanadium-aluminum-chromium alloy produced by the traditional thermite method, the uniformity of the present invention is greatly improved, and it can be used for the production of titanium alloys such as TB2, TB9, TB15, and TB16.

The invention discloses a sodium dichromate production roasting tail gas dust recycling device, and relates to the technical field of boiler equipment.The sodium dichromate production roasting tail gas dust recycling device comprises a mounting frame, a driving unit, a reducing unit, an anti-blocking unit and a recycling unit, the mounting frame is used for mounting and fixing the driving unit, the driving unit is used for working of a kiln body, and the reducing unit is used for changing the filter hole diameter of a filter screen; the anti-blocking unit is used for cleaning dust accumulated on the surface of the filter screen, the recovery unit is used for recovering the dust, and when the driving unit drives the kiln body to work and sodium dichromate production roasting is carried out, the filtering hole diameter of the filter screen is changed through the reducing unit, so that the situation that dust collection is affected due to the fact that the filter screen is blocked when the flow speed is too large is avoided; and dust attached to the surface of the filter screen is scraped through the anti-blocking unit to prevent blocking, the separated dust is secondarily recycled through the recycling unit, and the utilization rate of resources is increased.

The invention provides a method for leaching chromium in high-chromium tanning sludge, and belongs to the technical field of treatment of heavy metals in leather tanning sludge. The method comprises the following steps: mixing the high-chromium tannery sludge with dilute sulphuric acid, and carrying out acid leaching to obtain a chemical leaching solution and chemical leaching residues; diluting the chemical leaching residues, inoculating domesticated composite thiobacillus species, adjusting the pH value, adding a nutritional agent, and carrying out bioleaching to obtain a bioleaching solution and bioleaching residues; and finally, mixing the chemical leachate, the biological leachate, a sulfuric acid solution, a sodium dichromate solution and a glucose solution, adjusting the alkalinity, and stirring to obtain the chrome tanning agent. According to the method for leaching the chromium in the high-chromium tanning sludge, the removal rate of the chromium can reach 99% or above, the effect is remarkably superior to that of a single process, the method is a feasible and optimal process at the current stage, the chromium leaching solution is further processed and treated and enters a chromium tanning section to serve as a chromium tanning agent, and cyclic utilization is achieved.

The present application relates to a tinplate and a passivation method and system thereof, belonging to the technical field of steel material preparation. The method comprises: chemically passivating a tinplate substrate steel to be passivated so that a chromium-containing passivation film is formed on the surface of the tinplate substrate steel to obtain a first passivated plate; spraying passivating the first passivated plate so that a titanium-containing passivation film is formed on the surface of the first passivated plate to obtain a tinplate; replacing the current electrochemical passivation by first performing a sodium dichromate chemical passivation and then performing a titanium-containing passivation spraying passivation, thereby solving the problem of abnormal thickening of the passivation film caused by the electrochemical passivation.

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 discloses a sodium dichromate production roasting waste heat recycling device and relates to the technical field of boiler equipment. The device comprises a mounting frame, a rotary kiln, a driving unit, a detection scraping unit, a waste heat recycling unit and a fixed feeding unit. The mounting frame is used for mounting and fixing the rotary kiln and the driving unit. The rotary kiln is used for sodium dichromate production roasting. The driving unit is used for power output. The detection scraping unit is used for nodular detection and scraping of the rotary kiln inner wall. The waste heat recycling unit is used for raw material temperature detection. The fixed feeding unit is used for feeding the preheated raw material into the rotary kiln. When the sodium dichromate is produced and roasted in the rotary kiln, the detection scraping unit is driven by the driving unit to detect and scrape the nodules in the rotary kiln at any time, so that uneven roasting is avoided. The raw material is preheated to a preset temperature by the waste heat recycling unit, and the raw material is fed by the fixed feeding unit, so that waste heat recycling is realized.

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 present disclosure relates to a process for the production of alkali metal chlorate in a single compartment electrolytic cell, which avoids the need for addition of sodium dichromate to the process, in which unwanted side-reactions are reduced by using a cathode having an electrocatalytic top layer on a substrate that optionally also has one or more intermediate layers. The top electrocatalytic layer comprises an oxide of manganese and / or cerium.

The invention belongs to the technical field of industrial wastewater resource utilization, and particularly discloses a vanadium precipitation wastewater resource utilization method which comprises the following steps: hydrogen peroxide oxidation: adding industrial-grade hydrogen peroxide into vanadium precipitation wastewater; adjusting pH: adding liquid caustic soda into the oxidized vanadium precipitation wastewater to obtain vanadium-containing precipitate and filtrate 1; recycling chromium: enabling the filtrate 1 to pass through an ultrafiltration membrane to obtain chromium-containing regenerated liquid and filtrate 2, and performing evaporative crystallization on the chromium-containing regenerated liquid to obtain a sodium dichromate dehydrate product; recycling ammonium sulfate: adjusting the pH value of the filtrate 2 to 4-4.5 by using sulfuric acid, and enabling the filtrate 2 to enter an evaporative crystallization system to obtain a concentrated solution 1, an anhydrous sodium sulfate product and a condensate 1; cooling the concentrated solution 1, and performing solid-liquid separation to obtain a sodium sulfate decahydrate product and a concentrated solution 2; according to the method, after the vanadium precipitation wastewater is treated, vanadium, chromium and ammonia resources in the vanadium precipitation wastewater are fully recycled; according to the method, no wastewater is generated, and a new way is provided for vanadium precipitation wastewater resource utilization.

The invention discloses a method for preparing pseudo-boehmite by using sodium dichromate mother liquor to neutralize sodium aluminate and sodium chromate liquid, which comprises the following steps: simultaneously introducing the sodium dichromate mother liquor and the sodium aluminate and sodium chromate liquid into a stirring reactor in which soft water is added in advance, stirring to react, and increasing the concentration of reaction materials along with continuous introduction and finally achieving balance, after being balanced, the materials flow out from the overflow port and are transferred to the next process, and at the moment, the materials are still continuously fed, so that continuous feeding and continuous discharging are realized; and feeding the reacted material into an aging tank, heating, aging, washing with water, and drying to obtain the pseudo-boehmite product. According to the invention, resource utilization of the aluminum element in a chromium salt chemical production system is realized; meanwhile, the sodium dichromate mother liquor is used for providing an acid value for a neutralization reaction, and acid recycling is achieved; the pseudo-boehmite produced by the method disclosed by the invention has a relatively high specific surface area, a relatively large pore volume and a relatively concentrated average pore size.

The present invention relates to the technical field of liquid desulfurization slag remover, and specifically discloses a high-efficiency liquid desulfurization slag remover, wherein the raw materials include by mass: 5-15 parts of limestone powder, 0.1-1 parts of catalyst, 20-25 parts of oleic acid, 1-3 parts of sodium hydroxide, 0.1-1 parts of yttrium chloride, 0.0403-0.1550 parts of sodium fluoride, 0.0131-0.3830 parts of sodium dichromate, 1-3 parts of ethylenediamine, 2-5 parts of methyl acrylate, 5-15 parts of sodium tripolyphosphate, and 20-35 parts of sodium chlorite. The present invention also discloses a preparation method of the above-mentioned high-efficiency liquid desulfurization slag remover. The present invention has no odor, no irritating smell, and no polluting components to the body and the environment; it is not easy to block the nozzle, and it can not only effectively remove the slag body in the softened dust in the smoke, prevent coking, effectively reduce energy consumption and cost, and significantly improve the efficiency of the entire desulfurization system.

The invention discloses a method for efficiently preparing a chrome tanning agent with high quality from vitamin K3 chromium-containing waste liquid, and relates to the technical field of industrial waste liquid resource utilization. The method comprises the following steps: reacting sodium dichromate, concentrated sulfuric acid and the vitamin K3 chromium-containing waste liquid, completely oxidizing organic matters which are difficult to oxidize in the waste liquid by adopting a high-concentration hexavalent chromium oxidizing agent, reducing the content of the organic matters in the product, and increasing the content of chromium. The conventional pure glucose reduction is changed into oxidation of glucose to form a micromolecular reducing agent alcohol aldehyde acid, so that the organic matters in the waste liquid can be thoroughly eliminated. And key parameters are controlled through DCS control pipeline reaction, so that insoluble substances are reduced to the maximum extent, and the chromium content in the sugar reduction chromium powder is maximized and organic matters are minimized. The main quality index of the prepared chrome tanning agent exceeds the original national standard.

The invention discloses a method for preparing beta-menadione by using a compound emulsifier, which comprises the following steps: step 1, uniformly mixing high-molecular-weight alkanol and high-molecular alkyl sodium sulfonate to obtain the compound emulsifier; step 2, mixing beta-methylnaphthalene, water and a compound emulsifier to form an emulsion; step 3, mixing sodium dichromate with chromic anhydride, adding the mixture into water, and adding sulfuric acid to adjust the concentration of hexavalent chromium so as to form an oxidation solution; and 4, dropwise adding the oxidation liquid into the emulsion, carrying out a curing reaction on the reacted material, filtering, washing, and carrying out centrifugal dehydration to obtain the beta-menadione product. The invention has the following beneficial effects: the emulsion can be uniformly dispersed, the stability is better, the reaction speed with materials is high, the temperature range of reaction control is wider, and the side reaction is less; meanwhile, the compound emulsifier is better in stability and basically does not react with the oxidizing agent in the later period, the reaction process is more stable and continuous, and the obtained beta-menadione material is high in purity.

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.

Methods and compositions for quickly validating the cleaning performance in clean-in-place (CIP) and clean-out-of-place (COP) systems and on surfaces in high traffic areas. The solution comprises alkali metal hydroxides; one or more oxidizing compounds comprising sodium hypochlorite, potassium hypochlorite, sodium persulfate, potassium persulfate, 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 further comprises potassium tripolyphosphate, sodium tripolyphosphate, or other tripolyphosphates. A substrate is contacted with the solution and a color reaction may occur, indicating the presence of organic matter or non-organic soil. The color reaction may occur in less than 30 minutes and at temperatures from 10℃ to 60℃.

The invention discloses a method for preparing chromium oxide green from beta-menadione chromium-containing waste liquid, which comprises the following steps: step 1, adding a chromium source into the beta-menadione chromium-containing waste liquid to adjust the acid value, and heating the solution to form feed liquid A; step 2, adding sodium hydroxide and a reducing agent into the sodium dichromate or sodium chromate solution to prepare feed liquid B for later use; step 3, slowly and continuously adding the feed liquid B into the fully stirred feed liquid A, carrying out heat preservation and curing to form feed liquid C, carrying out plate-frame pressure filtration, pulping and washing on the feed liquid C to obtain a chromium hydroxide filter cake, and calcining and crushing the chromium hydroxide filter cake to obtain a chromium oxide green product; and performing chromium removal, filter pressing, concentration evaporation and electrolysis on the washing solution to obtain sodium hydroxide and sulfuric acid. The chromium oxide green prepared by the invention has lower hexavalent chromium content than other chromium oxide green, and is more stable; the cost of the method is lower than that of chromic anhydride calcination; the washing solution can also be converted into an important raw material in the chemical industry.

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.

The invention discloses a method for preparing reagent-grade potassium dichromate and industrial salt from sodium dichromate mother liquor, which comprises the following steps of: performing double decomposition reaction on the sodium dichromate mother liquor serving as a raw material and potassium chloride to prepare a crude potassium dichromate semi-finished product and a chromium-containing sodium chloride solution; and carrying out deep processing and purification on the crude potassium dichromate semi-finished product to produce reagent-grade potassium dichromate, carrying out evaporative crystallization on the chromium-containing sodium chloride solution, washing to reduce the chromium content, and adding a reducing agent to remove chromium so as to prepare industrial salt. According to the method, iron and aluminum impurities can be directly removed in the double decomposition reaction procedure, the yield is increased, meanwhile, the yield of the rough potassium dichromate semi-finished product is guaranteed, and a foundation is laid for subsequent production of high-quality reagent-grade potassium dichromate. Meanwhile, the method has the advantages of being high in operability, low in operation cost and easy to industrialize. And wastewater generated in the production process can be recycled, so that resource maximization is realized, and environmental pollution is avoided.

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.

The invention discloses a sodium dichromate production roasting waste heat recycling device, and relates to the technical field of boiler equipment.The sodium dichromate production roasting waste heat recycling device comprises a mounting frame, a rotary kiln, a driving unit, a detecting and scraping unit, a waste heat recycling unit and a fixed investment unit, the mounting frame is used for mounting and fixing the rotary kiln and the driving unit, and the rotary kiln is used for sodium dichromate production roasting; the driving unit is used for outputting power, the detecting and scraping unit is used for detecting and scraping nodules on the inner wall of the rotary kiln, the waste heat recycling unit is used for detecting the temperature of raw materials, and the fixed feeding unit is used for feeding the preheated raw materials into the rotary kiln. The driving unit drives the detecting and scraping unit to detect and scrape nodules in the rotary kiln all the time, uneven roasting is avoided, raw materials are preheated to the preset temperature through the waste heat recycling unit, the raw materials are fed through the fixed feeding unit, and recycling of waste heat is achieved.

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.