377 results about "Hexavalent chromium" patented technology

The invention relates to a modified chrome corundum ramming material and a preparation and construction process thereof, and belongs to the technical field of chrome corundum ramming materials. The ramming material comprises a material A, a material B and a material C, wherein the material A comprises chrome corundum aggregate, titanium dioxide coated aluminum oxide microspheres, calcium sulfide dehydrate and silicon carbide porous microspheres; the material B comprises chromium oxide-zirconium oxide composite nano powder, sodium thiosulfate pentahydrate, tricalcium phosphate and hexagonal boron nitride flaky crystals; and the material C comprises an aluminum dihydrogen phosphate-magnesium hydroxide compound, a calcium fluoride-aluminum oxide co-melt and a silane coupling agent. The preparation process comprises the steps of pretreatment of all the components, preparation of composite powder and layered preparation. The construction process comprises the steps of pretreatment, wet-process mixing, layered ramming, negative-pressure permeation, medium-temperature reaction, spraying curing, integral firing and the like. Generation of hexavalent chromium can be effectively inhibited, the thermal shock resistance, the mechanical strength and the heat-conducting property of the material are remarkably improved, and the material has the advantages of being good in environment friendliness, long in service life, excellent in construction performance and the like.

The invention discloses phenolic resin polymer spheres as well as a preparation method and application thereof, and belongs to the technical field of heavy metal adsorption in sewage treatment. According to the phenolic resin polymer sphere provided by the invention, the phenolic resin polymer sphere with specific morphology is obtained by improving the synthesis method of the phenolic resin polymer sphere. The adsorption site activity of the phenolic resin polymer sphere can be regulated and controlled in an illumination activation mode, the adsorption capacity and the adsorption efficiency on chromium are remarkably improved by promoting chemical adsorption, and the adsorption capacity and the adsorption efficiency are far higher than those of other chromium adsorbents reported in current literatures; the chromium adsorption capacity is far higher than that of a chromium adsorbent in light condition research. And meanwhile, chemical adsorption under illumination activation can improve the reduction capacity on hexavalent chromium and reduce the toxicity of hexavalent chromium. Moreover, the reduced trivalent chromium is directly adsorbed on the surfaces of the phenolic resin polymer spheres, so that the trivalent chromium does not need to be removed by a precipitation method, and the treatment process of the chromium-containing wastewater is saved.

The invention discloses a carbon / nano zero-valent iron composite material based on coal gasification slag and a preparation method of the carbon / nano zero-valent iron composite material. The method comprises the following steps: performing component separation on the coal gasification slag to obtain an iron-rich residual carbon component, mixing and grinding the iron-rich residual carbon component and sodium hydroxide according to a specific mass ratio, performing high-temperature calcination treatment in a nitrogen protective atmosphere, and performing hydrothermal activation reaction, solid-liquid separation, washing and drying to obtain the carbon / nano zero-valent iron composite material. The material shows excellent hexavalent chromium removal performance, can realize efficient removal of Cr (VI) in water within 5 minutes (the removal rate reaches 78.9%), and has remarkable structural stability. Synergistic activation of the endogenous iron-carbon components in the industrial solid waste is creatively achieved, a green and environment-friendly novel functional material solution is provided for heavy metal pollution treatment, and the method has important environmental benefits and industrial application value.

The utility model discloses a device for treating wastewater containing hexavalent chromium ions, which comprises an anode reaction zone, a cathode reaction zone, a buffer zone, an electrocoagulation reaction zone and an inclined tube settling zone which are communicated in sequence, a suspended partition plate is arranged between the anode reaction zone and the cathode reaction zone, a graphite plate array is arranged in the anode reaction zone, and the graphite plate array is arranged in the inclined tube settling zone. A porous carbon material is arranged in the cathode reaction zone, the cathode reaction zone is communicated with the buffer zone, the buffer zone is communicated with the electrocoagulation reaction zone, an iron pole plate array is suspended in the electrocoagulation reaction zone, the electrocoagulation reaction zone is communicated with the inclined tube settling zone, and the inclined tube settling zone is communicated with the inclined tube settling zone. And an inclined tube is suspended in the inclined tube settling region. According to the utility model, hexavalent chromium ions in water can be removed by only using electricity and a small amount of iron element, reducing agent chemicals and acid and alkali agents used for treating hexavalent chromium in the traditional process are greatly reduced, and the salt content of effluent is far lower than that of the traditional treatment process.

Hexavalent chromium (Cr (VI)) is widely applied to the industries of electroplating, spinning, leather tanning and chromium product manufacturing, and Cr (VI)-containing sewage has very strong biotoxicity and mutagenicity. Therefore, effective removal of Cr (VI) in industrial wastewater has important significance for protecting ecological environment and human health. As a novel bismuth-based oxychloride photocatalyst, the Bi4NbO8Cl material with the Aurivillius-Sillen structure has the advantages that the unique layered molecular structure of the Bi4NbO8Cl material is beneficial to the separation of photon-generated carriers, and the Bi4NbO8Cl material has good photocatalytic performance. On the basis of a Bi4NbO8Cl visible light response photocatalyst, the concentration of a glucose solution is regulated and controlled, carbon shell layers with different thicknesses are loaded, meanwhile, oxygen vacancy defects with different concentrations are formed, the visible light response Bi4NbO8Cl (at) C composite photocatalyst is obtained, and a good effect is achieved when the visible light response Bi4NbO8Cl (at) C composite photocatalyst is used for treating Cr (VI)-containing wastewater under the acidic condition.

Provided is a surface-treated steel sheet that can be produced without the use of hexavalent chromium and that combines excellent film corrosion resistance, coating corrosion resistance, film wet adhesion, coating secondary adhesion, and weldability. At least one side of the surface-treated steel sheet includes a Ni-containing layer, a metallic Cr layer on the Ni-containing layer, and an oxidized Cr layer on the metallic Cr layer. The water contact angle is 50° or less, and the total atomic ratio to Cr of K, Na, Mg, and Ca adsorbed on the surface is 5.0% or less.

The invention provides a remediation method for hexavalent chromium polluted underground water, and relates to the technical field of water treatment. According to the preparation method, rice hulls are adopted as raw materials and treated through an oxygen-limited pyrolysis-ferric salt dipping composite technology, and the rice hull-based iron-rich biochar material is obtained; loading microorganisms with the rice hull-based iron-rich biochar material to obtain an adsorption material; the adsorption material is used for carrying out adsorption treatment on the hexavalent chromium-containing polluted underground water. Aiming at Cr (VI) polluted underground water, a prepared rice husk-based iron-rich biomass material is adopted to load domesticated soil indigenous microorganisms, and the domesticated soil indigenous microorganisms are added into a nearly neutral Cr (VI) polluted soil / underground water reaction system, so that efficient reductive degradation of Cr (VI) is realized, and the influence mechanism of Fe < 3 + > is explored.

The invention belongs to the technical field of coating compositions, and discloses an electrophoretic coating with high weather resistance and high salt mist resistance and a preparation method thereof. According to the coating, a composite pigment and filler system formed by compounding a surface-modified sheet-shaped physical shielding filler and a calcium / zinc double-ion exchange type corrosion inhibition filler is adopted, and the surface-modified sheet-shaped physical shielding filler forms a compact labyrinth structure to prolong a corrosion medium permeation path; the corrosion inhibition filler releases Ca < 2 + > / Zn < 2 + > under the stimulation of chloride ions to generate a composite precipitation membrane in situ to block electrochemical corrosion; the two components are co-ground and pre-dispersed and chemically bonded with a resin matrix through a silane coupling agent, so that the compactness, the adhesive force and the self-repairing capability of the coating are improved. The electrophoretic coating does not contain hexavalent chromium and is suitable for high-end protection scenes such as automobiles and ocean engineering.

The invention discloses a hexavalent chromium solidification method suitable for acid / alkali soil, hexavalent chromium in the acid / alkali soil is solidified through combination of a low-carbon binding material and glucose, and the method comprises the following steps: mixing hexavalent chromium polluted soil with the low-carbon binding material, an exciting agent and a reducing agent, adding water, and uniformly stirring to obtain a mixture; the mixture is subjected to mold entering, forming, demolding and curing in sequence, and curing is completed; wherein the low-carbon cementing material comprises high-calcium fly ash, carbide slag and desulfurized gypsum; the exciting agent is silica fume water glass; the reducing agent is glucose. The solidified body prepared by the method can be used as a roadbed material, the purpose of treating waste with waste is achieved while hexavalent chromium is effectively prevented from being leached, and the defects of high carbon footprint, secondary pollution and the like of a traditional repairing means are overcome.

The invention relates to the field of vanadium and chromium separation, and particularly discloses a sodium vanadium solution treatment method which comprises the following steps: S100, adding an alkaline reducing agent into a sodium vanadium solution, and carrying out reduction of hexavalent chromium and selective precipitation reaction of trivalent chromium; s200, at the later stage of the reaction in the step S100, urea is added into a solution system, and a deep removal reaction of silicon and chromium is carried out; and S300, after the reaction in the step S200 is finished, solid-liquid separation is conducted, silicon-chromium slag and purified vanadium liquid are obtained, silicon-chromium oxide is obtained after the silicon-chromium slag is treated and can be used for smelting silicon-chromium alloy, and the purified vanadium liquid is subsequently used for preparing a high-purity vanadium oxide product. According to the method, the vanadium sodium salt solution obtained through a vanadium slag sodium salt roasting-water leaching process is used as a raw material, hexavalent chromium in the solution is reduced through an alkaline reducing agent, selective precipitation separation of hexavalent chromium and vanadium is achieved, and meanwhile urea is supplemented to conduct synergistic precipitation removal on silicon in the solution.

The invention is applicable to the technical field of trailer part treatment, and provides a trailer part surface coating treatment process which comprises the following steps: performing high-frequency induction quenching on a trailer ball base body; a copper bottom layer is electroplated on the trailer ball base body, and a bright nickel layer is electroplated on the copper layer; a microcrack nickel layer is electroplated on the bright nickel layer, and a trivalent chromium layer is electroplated on the microcrack nickel layer through a trivalent chromium plating solution; the trailer ball base body electroplated with the trivalent chromium layer is subjected to nanometer hole sealing treatment; applying a layer of polysiloxane or UV (ultraviolet) curing type super-hard transparent finish paint on the surface subjected to hole sealing treatment in a spraying manner; a layer of micro-crack nickel is electroplated on the bright nickel layer, and a micro-crack network of the micro-crack nickel provides a preset and uniform stress release channel for a subsequent chromium layer, so that the internal stress of the chromium layer is dispersed, the brittleness of the chromium layer is greatly reduced, and the impact resistance of the chromium layer is remarkably improved; and a trivalent chromium chromium plating process is adopted to replace traditional hexavalent chromium chromium plating, so that the environmental pollution and toxicity are greatly reduced, and the requirements of modern environmental protection regulations are better met.

The invention belongs to the technical field of solid waste recycling and wastewater treatment, and particularly relates to a method for treating chromium-containing wastewater by adopting organic amine flue gas desulfurization residues. According to the method, organic amine flue gas desulfurization residues are used as a reducing agent, phosphoric acid is used for controlling the pH value of wastewater, hexavalent chromium is reduced into trivalent chromium under the acidic condition, meanwhile, desulfurization ash is converted into a melamine phosphate flame-retardant material, and trivalent chromium is separated from water in a precipitation form under the neutral condition; after the precipitate is roasted, chromium sesquioxide powder with relatively high purity is obtained, residual ammonia nitrogen in the wastewater, the added magnesium salt and residual phosphoric acid in the water form struvite precipitate, so that the ammonia nitrogen in the water is removed, and the struvite can be used as a raw material of a slow-release fertilizer. According to the method, the treatment cost of the vanadium extraction wastewater and the flue gas desulfurization slag is remarkably reduced, valuable elements are fully recycled, and resource utilization of flue gas desulfurization waste in a waste-to-waste mode is achieved.

The invention provides a step-by-step leaching remediation method for chromium-contaminated soil, which comprises the following steps: mixing the chromium-contaminated soil and a first leacheate, carrying out first oscillation, then adding a second leacheate into the mixture, and carrying out second oscillation to obtain the remediated soil, the first leacheate comprises sodium salt; the second leacheate comprises organic acid and ferric salt; the temperature of the second oscillation is 70 DEG C to 90 DEG C. The method comprises the following steps: desorbing and releasing hexavalent chromium adsorbed on the surfaces of soil particles by using a sodium salt eluting agent, dissolving the soil particles to promote release of insoluble hexavalent chromium, and dissolving the soil particles containing high-concentration insoluble hexavalent chromium by using a composite eluting agent of organic acid and ferric salt under a high-temperature condition. And when the hexavalent chromium is released, the hexavalent chromium is efficiently reduced and stabilized, so that the aim of removing the hexavalent chromium in the polluted soil is fulfilled.

The invention relates to the technical field of sewage treatment, and discloses a photocatalytic material and a preparation method and application thereof.The method comprises the following steps that bismuth nitrate pentahydrate and sodium bromide are added into a mannitol solution according to the molar ratio of 1: 1.5, and ultrasonic dispersion is conducted to form turbid liquid; adding arginine into the turbid liquid, wherein the molar ratio of the arginine to the bismuth nitrate pentahydrate is (0-2.5): 1; adjusting the pH value of the turbid liquid and stirring to obtain a precipitate; the precipitate is filtered, washed and dried, and the photocatalytic material nVBi-(110) BiOBr is obtained.By means of the photocatalytic material, the removal rate of hexavalent chromium in alkaline wastewater with the pH being 7-10 can still exceed 90% within a short time, the photocatalytic material shows excellent stability and reaction activity, the technical problem that hexavalent chromium is difficult to remove efficiently in the alkaline environment is successfully solved, and the photocatalytic material has good application prospects. The method has important environmental application value and popularization potential.

The invention discloses a preparation method of a wear-resistant coating of a piston rod, and aims to solve the problems of low bonding strength, high porosity, easiness in oxidation, large residual stress and the like of an existing coating. The method comprises the following steps: firstly, carrying out alkaline oil removal and sand blasting roughening pretreatment on a piston rod matrix, and carrying out sand blasting for 5-10 minutes by adopting aluminum oxide sand grains of 120-200 meshes under the pressure of 0.4-0.6 MPa; then NiCrMo alloy powder with the thickness of 15-45 microns is sprayed through high velocity oxy-fuel to form a bottom layer with the thickness of 80-120 microns, and the binding force of the coating and a base body is enhanced; then, WC-Co-Cr composite ceramic powder with the mass fraction of WC being 70%-85% is subjected to laser cladding, a wear-resisting layer of 300-500 microns is prepared, and argon at the speed of 10-15 L / min is synchronously introduced to prevent oxidation; finally, under the vacuum degree of 1 * 10 <-3 >-1 * 10 <-2 > Pa, the temperature is increased to 400-500 DEG C at the speed of 5-10 DEG C / min, heat preservation is conducted for 2-3 h Through gradient coating design and parameter synergy, the compactness of the coating exceeds 99%, the hardness reaches HV1200-1500, the bonding strength exceeds 70 MPa, compared with a traditional process, the wear-resistant life is prolonged by 3.2 times, the salt spray corrosion resistance exceeds 1500 hours, hexavalent chromium pollution is avoided, and the coating has remarkable industrial application value.

The invention discloses a hexavalent chromium water quality on-line monitoring system and method based on deep learning, and relates to the technical field of water quality on-line monitoring, and the method comprises the following steps: arranging sensor networks at key parts of a to-be-monitored water body at equal intervals, and storing original time sequence data of each sensor into a historical water quality database according to timestamps; extracting a water body transient disturbance component and a sensor adsorption memory component, and inputting the components into the time sequence component predictor; calculating a hexavalent chromium risk index based on a prediction residual error of the time sequence component predictor and a physical model deviation, and carrying out regeneration or alarm processing according to a self-adaptive threshold strategy; when a regeneration event is triggered, the deviation recovery amount of each sensor before and after cleaning is recorded, an incremental training sample is formed, and the model weight of the time sequence component predictor is updated online. According to the method, the problem that sensor drift is easily misjudged as pollution or a short-time peak value is easily misjudged as noise due to the fact that the original signal contains multiple time scale components but many methods cannot effectively separate on the time scale is solved.

The present invention discloses a photoelectrochemical sensor for the detection of hexavalent chromium ions. The photoelectrochemical sensor is a modified ITO glass electrode, and the modification material is a photosensitive composite film with high-sensitive optoelectronic activity. Due to the strong absorption effect of the photo electron acceptor on the photo electrons generated by the photosensitive complex, the sensor can generate a strong cathodic photoelectrochemical signal. By utilizing the enrichment performance of the photosensitive composite film for hexavalent chromium ions, and under the conditions of light illumination and an applied bias voltage, weakly conductive reduction products can be generated on the surface of the photosensitive composite film, which effectively reduces the conductivity of the photosensitive composite film, inhibits the optoelectrochemical activity, hinders the transfer of photo electrons to the electron acceptor, quenches the photocurrent, and the quenched photocurrent has a correlation with the content of hexavalent chromium. In the present invention, the preparation of the sensor is simple, the cost is low, the response is fast, the sensitivity is high, the detectable range is wide, and the detection limit is as low as 5 pM. The rapid determination of hexavalent chromium in environmental water bodies, drinking water and food can be realized.

The invention discloses bacillus cereus with wide pH adaptability and application of the bacillus cereus in soil or underground water heavy metal remediation, the strain is named as bacillus cereus GS and preserved in the China Center for Type Culture Collection (the preservation number is CCTCC NO: M 20241939), and the bacillus cereus is named as bacillus cereus GS and preserved in the China Center for Type Culture Collection (CCTCC). The strain is high in environmental adaptability and high in remediation efficiency, can show good reduction and endurance capacity to various heavy metal pollutants under the wide environmental conditions that the pH ranges from 4 to 10 and the temperature ranges from 16 DEG C to 37 DEG C, and is particularly suitable for in-situ remediation of high-concentration contaminated soil; experimental results represented by hexavalent chromium show that the removal rate of the strain in 1000 mg / kg hexavalent chromium contaminated soil within 7 days can reach 70-100%, the dependence of an existing microbial remediation technology on a low-concentration and alkaline environment or a long remediation period is broken through, and an efficient solution is provided for green bioremediation of multiple types of heavy metal contaminated sites.

The invention relates to the field of vanadium and chromium separation, and particularly discloses a method for removing impurities phosphorus, chromium and silicon in a sodium modified vanadium solution, which comprises the following steps: S100, adjusting the pH value of the sodium modified vanadium solution to enable the pH value of a solution system to be 8.0-9.0 at room temperature to obtain a pretreated sodium modified vanadium solution; s200, heating the pretreated sodium vanadium solution, sequentially adding a reducing agent and a polyelectrolyte into the solution while stirring, and carrying out phosphorus and chromium removal reaction while stirring; s300, after the removal reaction of phosphorus and chromium is carried out for a period of time, adding a silicon removal agent, and carrying out a removal reaction of silicon; and S400, after the silicon removal reaction is finished, standing sedimentation and solid-liquid separation are carried out, impurity-removed slag is washed with water and then merged into the filtrate, and purified vanadium liquid is obtained. According to the method, firstly, glucose is adopted to selectively reduce hexavalent chromium into trivalent chromium under the weakly alkaline condition, pentavalent vanadium is not reduced, the trivalent chromium forms chromium phosphate and chromium hydroxide precipitates in a weakly alkaline solution, and meanwhile, the chromium removal efficiency is improved in a polyelectrolyte coagulation mode.

To provide a heavy metal insolubilizing material for insolubilizing heavy metal contained in a heavy metal contaminant (for example, incineration ash, soil, and drainage water), which can exhibit an excellent insolubilization effect to a plurality of kinds of heave metal (for example, arsenic and hexavalent chromium), in a short time (for example, 2 to 3 hours).SOLUTION: A heavy metal insolubilizing material contains an iron compound composed of either or both of ferrous sulfate monohydrate and ferrous chloride tetrahydrate, and a magnesium compound composed of one or more selected from the group consisting of magnesium sulfate heptahydrate, magnesium sulfate nonhydrate, and magnesium sulfite hexahydrate. A ratio of the iron compound in the total amount of the iron compound and the magnesium compound is 5 to 80 mass%. The heavy metal insolubilizing material can be prepared in a powdery form.SELECTED DRAWING: None

The utility model relates to a water-soluble hexavalent chromium filtering and collecting device, which belongs to the field of laboratory collection, and comprises a Buchner funnel (1) and a tray (2), the Buchner funnel (1) comprises a funnel opening (3) and a funnel neck (4), the funnel neck (4) is arranged at the bottom of the funnel opening (3), the funnel neck (4) is connected with the tray (2), the Buchner funnel (1) is taken out, and a beaker (11) filled with filtrate is taken out at the same time. The Buchner funnel (1) is provided with a suction filtration bottle (5), the suction filtration bottle (5) is provided with an extraction opening (6), the extraction opening (6) is connected with an extraction pipe (7), the extraction pipe (7) is connected with the suction filtration bottle (5), and the suction filtration bottle (5) is connected with the suction filtration bottle (5). The exhaust pipe (7) is connected with a vacuum pump (8), so that the filtering effect is improved, and the filtering is faster.

One aspect of the present invention relates to an MFI-type zeolite catalyst containing chromium that contains hexavalent chromium.

The application relates to a modified chrome-corundum ramming mixture and a preparation and construction process, and belongs to the technical field of chrome-corundum ramming mixtures. The ramming mixture comprises A material, B material and C material, the A material comprises chrome-corundum aggregates, titanium dioxide-coated alumina microspheres, calcium sulfide dihydrate and porous silicon carbide microspheres; the B material comprises chromium oxide-zirconium oxide composite nano powder, sodium thiosulfate pentahydrate, tricalcium phosphate and hexagonal boron nitride flaky crystals; and the C material comprises an aluminum dihydrogen phosphate-magnesium hydroxide compound, a calcium fluoride-alumina eutectic body and a silane coupling agent. The preparation process comprises pretreatment of components, preparation of composite powder and layered preparation; and the construction process comprises the steps of pretreatment, wet mixing, layered ramming, negative pressure infiltration, medium-temperature reaction, spraying and curing and overall sintering. The application can effectively inhibit the generation of hexavalent chromium, significantly improve the thermal shock resistance, mechanical strength and heat conduction performance of the material, and has the advantages of good environmental protection, long service life, excellent construction performance and the like.

The invention belongs to the technical field of metal surface treatment, and discloses an electroplating additive suitable for a steel and alloy surface bright wear-resistant corrosion-resistant hexavalent chromium coating, which is characterized by comprising an organic compound, an inorganic acid, a metal inorganic compound and water, the organic compound comprises a mixture of a fluorine-free compound and a fluorine-containing compound. The method can be widely applied to decorative chromium plating and functional hard chromium plating, the electroplating temperature is 40-70 DEG C, the electroplating time of the decorative chromium plating is 1-10 min, the electroplating time of the hard chromium plating is 20 min or above, the hardness can reach 900 HV or above, the glossiness of the surface of a workpiece can be kept through the decorative plating and the hard chromium plating, the current efficiency can reach about 23%, and the service life of the workpiece is prolonged. The current use requirements of high efficiency, stability and environmental protection are met, and the market prospect is good.

The utility model provides a kind of electroplating wastewater hexavalent chromium reduction automatic dosing control device, including pH adjusting pool, reduction reaction pool, sampling pump, video recognition system, control assembly, dosing pump and dosing tank;Reduction reaction pool is connected after pH adjusting pool;Sampling pump is connected with reduction reaction pool by sampling pipeline, and video recognition system is connected after sampling pump, and video recognition system is reconnected to reduction reaction pool by reflux pipeline after video recognition system;Video recognition system is connected with control assembly, and control assembly is connected with dosing device, so that control assembly controls dosing device according to video recognition system signal.The utility model uses video recognition system to replace ORP controller, without accurate control wastewater pH value.

The present application relates to the technical field of groundwater pollution remediation, and particularly relates to a method and device for in-situ remediation of hexavalent chromium contaminated groundwater, wherein the device comprises a multifunctional well group, a medicament supply system, an aeration system, a monitoring system and a control system; the multifunctional well group comprises a plurality of multifunctional wells; the medicament supply system is used for pretreating medicaments, modified composite reducing agents and composite functional bacteria liquid respectively; the control system is used for receiving monitoring data; the control system is also used for displaying monitoring data and equipment operating states, and setting operating parameters by a user; the control system is also used for automatically adjusting medicament dosing amount, aeration flow and aeration pressure according to monitoring data and operating parameters set by the user. Through the design of the multifunctional well group, the medicament supply system and the aeration system, the hexavalent chromium contaminated groundwater can be simultaneously subjected to chemical reduction, biological reinforcement and adsorption fixation, so that the three processes are coordinated to realize rapid, efficient and long-acting remediation of the hexavalent chromium contaminated groundwater.

The invention provides a preparation method of high-purity nicotine. The content of nitroso substances in an obtained nicotine finished product is lower than the PPB level, and the content of single heavy metals such as lead, cadmium, mercury and hexavalent chromium is also lower than the PPB level. The low-content nitroso substance concentration and heavy metal concentration can effectively reduce the harm of the synthesized nicotine to the human body, and the method provided by the invention can realize continuous industrial production of nicotine, and fills the blank of the demand of the market for high-purity L-nicotine.

This invention discloses an upflow electrochemical treatment device and method for treating wastewater containing hexavalent chromium. The device includes a cylindrical inner reaction chamber and a double-layer reaction chamber. The inner reaction chamber contains a mesh-like ruthenium-iridium-titanium anode and a carbon fiber felt membrane cathode. The double-layer reaction chamber includes an external overflow chamber and an internal upflow chamber. The method includes the following steps: S1, preliminary preparation; S2, wastewater injection; S3, continuous wastewater treatment; S4, detection. This invention mainly uses an upflow electrochemical water purification membrane for wastewater treatment, which can efficiently reduce highly toxic hexavalent chromium to less toxic trivalent chromium, effectively reducing the toxicity of the wastewater. Simultaneously, it utilizes the oxygen released during the reduction of hexavalent chromium to achieve the simultaneous generation of hydrogen peroxide, improving resource utilization and reducing treatment costs.

The invention discloses a green, environment-friendly and efficient vanadium extraction method, and relates to a roasting additive and a roasting process thereof, and the method is realized by the following steps: mixing vanadium slag and a calcium oxalate additive, roasting, and treating the roasted clinker with acid to obtain a vanadium ion-containing solution and low-solubility residues; and treating the vanadium-containing ion solution to obtain a vanadium product with high vanadium content. According to the method, vanadium in the vanadium slag can be efficiently and rapidly separated and purified, an existing vanadium extraction process is simplified, the yield of vanadium is increased, the temperature and time needed by roasting the vanadium slag through a traditional calcium method are reduced, the risk of percolation of vanadium extraction tailings through a traditional sodium method is reduced, and the problems that in the traditional vanadium slag vanadium extraction process, the vanadium extraction rate is low, energy consumption is high, and the process is complex are solved; no harmful waste is discharged in the whole process, and no hexavalent chromium leakage risk exists in the leached tailings. The method is simple in process, energy-saving, environment-friendly, high in operability and wide in application prospect.

This invention relates to the field of chromium slag resource utilization technology, specifically to a method for pre-reduction enhanced oxidation extraction of chromium from chromium slag, comprising: S1, mixing calcium-free roasted chromium slag, carbonaceous reducing agent, and sodium carbonate in a mass ratio of 1:(0.4~0.9):(0.05~0.25) and pressing them into shape to obtain a chromium slag preform; S2, under an inert atmosphere, reducing and roasting the chromium slag preform at 850~1050℃ for 30~150 min to generate sodium chromite, and cooling it to room temperature with the furnace to obtain a pre-reduced chromium slag mixture; S3, under an oxygen-containing atmosphere, oxidizing and roasting the pre-reduced chromium slag mixture at 850~1050℃ for 30~150 min to convert trivalent chromium into water-soluble hexavalent chromium compounds, and air-cooling it to room temperature to obtain a roasting product; S4, stirring and leaching the roasting product in an acidic solution, separating the solid and liquid to obtain a leaching residue and a leachate containing hexavalent chromium. The pre-reduction stage enables lattice reconstruction and micropore optimization, creating favorable reaction conditions for the subsequent oxidation stage, thereby significantly improving the oxidation conversion efficiency of chromium.