669 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 preparation method of a layered oxide material sodium chromite for a sodium-ion battery, which comprises the following steps: directly mixing a reducing sodium source and a hexavalent chromium source as raw materials, and carrying out solid-phase oxidation-reduction reaction to prepare the layered oxide material sodium chromite for the sodium-ion battery. The preparation method of the layered oxide material sodium chromite of the sodium ion battery has the characteristics of simple process and excellent electrochemical performance.

The invention discloses a selective separation and resource utilization method of chromium in a sodium vanadium solution, which comprises the following steps: S1, measuring a predetermined volume of sodium vanadium solution, and heating to a predetermined temperature; s2, a preset amount of divalent manganese salt is added into the sodium vanadium solution, so that hexavalent chromium is subjected to a reduction reaction; s3, after the reaction is finished, carrying out solid-liquid separation and washing to obtain chromium and vanadium removed liquid and precipitates; s4, vanadium precipitation and calcination are conducted on the chromium and vanadium removal liquid, and a vanadium oxide product is obtained; and calcining the precipitate at high temperature to obtain the chromium-manganese oxide. According to the method, the sodium vanadium solution is used as a raw material, the divalent manganese salt is used as a reducing agent, hexavalent chromium is reduced into trivalent chromium, the trivalent chromium generates chromium hydroxide precipitate under the alkaline condition, vanadium is not reduced and is reserved in the solution, and efficient separation of vanadium and chromium is achieved; the dechromed vanadium liquid is subjected to vanadium precipitation and calcination, and a vanadium oxide product is obtained; after the precipitate is subjected to high-temperature calcination, chromium-manganese oxide is obtained and can be used for preparing chromium-manganese alloy, and resource utilization is achieved.

The invention relates to the technical field of adsorbent preparation, in particular to an ammonia modified porous carbon adsorbent and a preparation method thereof. The preparation method of the ammonia modified porous carbon adsorbent comprises the following steps: carrying out hydrothermal acid leaching on gasified fine residues and an acid solution to obtain acid leaching residues; stirring the acid leaching residues in an alkali solution, washing and drying to obtain a porous carbon material; and dipping the porous carbon material in a tetraethylenepentamine solution, and then drying to obtain the ammonia modified porous carbon adsorbent. The ammonia modified porous carbon adsorbent is successfully constructed by taking a porous carbon material derived from coal gasification fine slag as a substrate and further adopting a surface ammonia functionalization modification strategy. The preparation method is simple, the raw materials are easy to obtain, and the prepared ammonia modified porous carbon adsorbent has a good adsorption effect on methylene blue and hexavalent chromium. According to the method, high-added-value resource utilization of the coal gasification solid waste is achieved, and a solution is provided for treatment of the dye wastewater and the heavy metal wastewater.

The invention discloses a cyanide-free cadmium-iron alloy plating process for high-strength structural steel. The cyanide-free cadmium-iron alloy plating process comprises the step that a nickel-titanium alloy plating layer, a cyanide-free cadmium-iron alloy plating layer and a hexavalent chromium passivation film are sequentially prepared on a high-strength structural steel substrate from inside to outside. The prepared sample piece is subjected to a hydrogen brittleness test according to HB 5067.1-2005 Part 1 of hydrogen brittleness test of plating process: Mechanical Method, and the test result meets the standard requirement; the surface of a plated part is free of white rust after being subjected to an acetate mist test for 400h according to GB / T 10125-2021 Artificial Atmosphere Corrosion Test Salt Spray Test, and a plating layer of the plated part has excellent corrosion resistance; according to GB / T 5270-2005 < GB / T 5270-2005 < GB / T > 5270-2005 < GB / T > 5270-2005 > < GB / T > 5270-2005 > < GB / T > 5270-2005 > < GB / T > 5270-2005 > < GB /

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 invention relates to the technical field of water treatment, and discloses a sewage mixing flocculation sedimentation tank with a dosing system and a sewage treatment process, the sewage treatment process comprises the following steps: (1) sewage enters a pretreatment unit, and large-particle suspended solids are removed; (2) enabling the sewage to flow into a pH regulating tank, adding a pH regulator through a dosing system, and regulating the pH value to 9-11; (3) passing through a coagulation reaction tank, adding ferrous sulfate to reduce hexavalent chromium into trivalent chromium, and promoting a flocculation reaction; and (4) further adding polyaluminum chloride through the flocculation reaction tank to form floc. Through a multi-unit combined treatment process, suspended solids and various heavy metals in the sewage are gradually removed, and the effluent quality is ensured to reach the standard. Compact and reasonable process layout is adopted, the occupied area is reduced, and the device is suitable for small and medium-sized sewage treatment plants. An automatic dosing control system is introduced, dosing is accurate, and the operation cost is reduced.

The invention relates to the technical field of natural attenuation monitoring, and discloses a technical method for monitoring natural attenuation of hexavalent chromium polluted groundwater, and the method comprises the following steps: judging whether a hexavalent chromium groundwater polluted land parcel is suitable for adopting a natural attenuation monitoring technology or not; if yes, updating the plot conceptual model and carrying out simulation analysis, and integrating various feasibility evaluation factors to judge whether the natural attenuation monitoring technology is feasible or not; if yes, an application scene is determined, a monitoring scheme for monitoring the natural attenuation project is designed, and a periodic target of project operation is formulated; and finally, evaluating the monitoring natural attenuation implementation effect from two aspects of process evaluation and end evaluation. The method has the advantages of being scientific, efficient and high in practicability, and reference and technical support can be provided for underground water risk management and control of the chromium pollution site in China.

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.

The invention relates to the technical field of adsorbent preparation and hexavalent chromium Cr (VI) adsorption, in particular to application of an ammonia modified porous carbon adsorbent in Cr (VI) adsorption. According to the method, an ammonia modified porous carbon adsorbent is added into a water sample containing Cr (VI) for adsorption, so that Cr (VI) in the water sample is removed; the preparation method of the ammonia modified porous carbon adsorbent comprises the following steps: carrying out hydrothermal acid leaching on gasified fine residues and an acid solution to obtain acid leaching residues; stirring the acid leaching residues in an alkali solution, washing and drying to obtain a porous carbon material; and dipping the porous carbon material in a tetraethylenepentamine solution, and then drying to obtain the ammonia modified porous carbon adsorbent. The ammonia modified porous carbon adsorbent is successfully constructed by taking a porous carbon material derived from coal gasification fine slag as a substrate and further adopting a surface ammonia functionalization modification strategy. The ammonia modified porous carbon adsorbent has a good adsorption effect on Cr (VI).

The present invention relates to the field of photocatalysis, and relates specifically to a biochar / titanium dioxide composite photocatalytic material, a preparation method therefor, and a use thereof. The preparation method comprises the following steps: pretreating wheat straw, then transferring same into a crucible, and carrying out a carbonization treatment to obtain straw biochar; mixing the straw biochar with hydrochloric acid, followed by washing and then drying to obtain biochar; mixing butyl titanate with absolute ethanol to obtain solution A, and thoroughly and uniformly mixing absolute ethanol with distilled water and acetic acid to obtain solution B; adding solution B dropwise into solution A, performing magnetic stirring and then adding the biochar, continuing to stir, followed by aging and then drying, grinding, and then calcining to obtain a biochar / titanium dioxide composite photocatalytic material. The present invention provides an efficient, sustainable, and economical solution for the treatment of hexavalent chromium wastewater, promoting the application of biochar and nano titanium dioxide composite materials in the environment field.

The invention discloses a stirring and heating device and method for measuring hexavalent chromium in soil and sediment, the stirring and heating device comprises a stirring and heating cabin and a power cabin, a stirring and heating cabin cover is arranged above the stirring and heating cabin, a magnetic stirring device and a driving motor are arranged in the power cabin, and a beaker bracket and a heating pipe are arranged in the stirring and heating cabin; the heating pipe is located on the inner bottom face of the stirring and heating cabin, the beaker bracket is located above the heating pipe, stirring and heating cabin cover open holes and a stirring and heating cabin cover handle are arranged above the stirring and heating cabin cover, and the number and the position of the stirring and heating cabin cover open holes correspond to those of the beaker bracket. The lower end of the central rotating shaft is connected with an output shaft of the driving motor, the upper end of the central rotating shaft penetrates through the central position of the stirring and heating cabin cover, and an infrared temperature measuring device is arranged at the upper end of the central rotating shaft. The method can effectively improve the detection efficiency and precision of hexavalent chromium in soil and sediments.

The invention discloses a repairing agent and method for repairing hexavalent chromium contaminated soil. The repairing agent is composed of pyroligneous liquor and ferrite, the addition amount of the ferrite in each milliliter of the pyroligneous liquor is 0.006-0.08 g, and the concentration of the pyroligneous liquor is 50-100%. The method comprises the following steps: adding a repairing agent into the chromium-contaminated soil, adding deionized water, uniformly stirring the soil, keeping the water content of the soil, standing and maintaining, reducing hexavalent chromium in the soil into trivalent chromium, and reducing and removing the hexavalent chromium in the chromium-contaminated soil. The method is high in hexavalent chromium removal efficiency, high in operability, good in practicability and high in applicability in strong alkaline soil.

The invention relates to a method for cooperatively treating chromium-containing sludge by using a waste dust collecting bag and blast furnace dust. The method comprises the following steps: roasting the waste dust collecting bag to obtain roasted ash of the waste dust collecting bag; mixing the roasting ash and blast furnace fly ash; adding the mixed material 1 into the chromium-containing waste liquid, and carrying out plate-frame pressure filtration to obtain a mixed material 2; the method comprises the following steps: cutting iron ore into blocks, drying, roasting after drying, quickly water-cooling a roasted product, grinding after water-cooling, and magnetically separating a ground product to obtain spinel iron ore concentrate containing ferrochrome and low-chromium tailings. According to the method, the waste dedusting cloth bag and the blast furnace dedusting ash are used as curing agents, curing of heavy metal chromium in the chromium-containing sludge is achieved, the leaching rate of hexavalent chromium and total chromium in the obtained product is far lower than the standard limit value, harmless treatment of the chromium-containing sludge is achieved, the purpose of treating waste with waste is achieved, the obtained ferrochrome spinel can be recycled through magnetic separation, and the method is environmentally friendly. The produced low-chromium tailings can be directly buried or used as building materials.

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 discloses a remediation agent for high-concentration hexavalent chromium polluted soil and a preparation method and a remediation method thereof, and belongs to the technical field of soil pollution remediation. The remediation agent for the high-concentration hexavalent chromium contaminated soil comprises an acidic precursor, an iron-sulfur reducing agent and a synergist, the acidic precursor comprises organic acid and propylene glycol alginate; the iron-sulfur reducing agent comprises an iron-based reducing agent and a sulfur-based reducing agent; the synergist is prepared from sophorolipid and alkyl glucoside. The remediation agent can be used for high-concentration hexavalent chromium contaminated soil, hexavalent chromium in the soil is exposed in a Cr < 6 + > ion form as much as possible by replacing the hexavalent chromium in the soil, then the hexavalent chromium is converted into trivalent chromium by using a reducing agent, and the removal efficiency of the hexavalent chromium reaches up to 99.6%. In addition, the soil remediation agent is simple in use mode, rapid and thorough in reaction and lasting in effect.

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 relates to the technical field of remediation of heavy metal polluted underground water, and discloses a biochar-loaded nano iron-copper material for treating hexavalent chromium wastewater as well as a preparation method and application of the biochar-loaded nano iron-copper material. The preparation method of the material comprises the following steps: S1, mixing waste white tea branch and leaf powder with deionized water, heating in a water bath, and carrying out vacuum suction filtration to obtain a white tea extracting solution and white tea branch and leaf powder; s2, the white tea branch and leaf powder is placed in a drying oven to be dried, pyrolyzed, ground and sieved, and charcoal powder is obtained; s3, mixing the charcoal powder and the white tea extract in a liquid nitrogen gas environment to obtain a suspension; and dropwise adding an iron salt solution and a bivalent copper salt solution, and after the synthesis reaction is completed, centrifuging, washing and freeze-drying to obtain a finished product of the biochar-loaded nano iron-copper material. The biochar-loaded nano iron-copper material has higher reducing capacity for hexavalent chromium ions in water, is prepared from plant wastes and the like, does not involve the use of strong acids, strong bases and strong reducing agents, and has lower economic cost and higher environmental benefits.

The invention relates to the technical field of cement preparation, and particularly discloses dry-process clinker cement and a preparation process thereof. The dry-process clinker cement comprises the following raw materials in parts by weight: 180-200 parts of limestone; 30-50 parts of iron tailing powder; 20 to 30 parts of coal gangue; 10 to 20 parts of fly ash; 5-8 parts of calcium fluoride; 5-8 parts of nano silicon dioxide; 1-5 parts of nano calcium carbonate; 1-5 parts of sodium sulfide; 1-5 parts of a charcoal-ferrous sulfate loading material; 100 to 200 parts of water; 5-20 parts of a sintering aid; the biochar-ferrous sulfate loading material is obtained by loading ferrous sulfate on biochar particles. According to the dry-process clinker cement disclosed by the invention, the reduction activity and chromium removal efficiency of the ferrous sulfate can be effectively enhanced through the charcoal-ferrous sulfate loading material, so that hexavalent chromium in the cement can be efficiently removed by using a relatively small amount of ferrous sulfate, and the cement can keep relatively good compressive strength while the cost is reduced.

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 technical field of hazardous waste resource utilization, in particular to a method for recycling overhaul slag and chromium-containing aluminum mud. The overhaul slag contains fluoride, cyanide and carbon, the chromium-containing aluminum mud contains aluminum and hexavalent chromium, and the method comprises the following steps: carrying out redox reaction on inorganic acid, the chromium-containing aluminum mud and the overhaul slag to obtain a decyanation material containing fluoride, carbon, aluminum and chromium; carrying out a precipitation reaction on the decyanation material by using a calcium-containing alkaline oxide to obtain a precipitation material containing chromium, aluminum, carbon and fluorine; carrying out chlorination reaction on the precipitation material by using preheated chlorine to obtain aluminum-containing chlorinated flue gas and chromium-containing chlorinated slag; separating and purifying the aluminum-containing chlorinated flue gas to obtain an aluminum-containing solid phase; and washing the chromium-containing chlorination slag to obtain a trivalent chromium-containing solution. According to the method, the chromium-containing aluminum mud and the overhaul slag are used as raw materials, and the removal effect of toxic elements in the overhaul slag and the chromium-containing aluminum mud and the recovery rate of valuable elements such as aluminum and chromium can be synchronously improved through the oxidation-reduction reaction, the precipitation reaction and the chlorination reaction.

It is provided a surface-treated steel sheet that can be produced without using hexavalent chromium and has excellent film wet adhesion and coating secondary adhesion as well as high film corrosion resistance and coating corrosion resistance. It is a surface-treated steel sheet having: a steel sheet; a metallic Cr layer disposed on at least one surface of the steel sheet; and a Cr oxide layer disposed on the metallic Cr layer, and the surface-treated steel sheet has a water contact angle of 50° or less and a total atomic ratio of K, Na, Mg, and Ca adsorbed on the surface to Cr of 5% or less.

The present invention provides a remediation composition for soil contaminated with hexavalent chromium and a soil remediation method. The composition comprises catechin, flavonoid isorhamnetin and humic acid with a mass ratio of 1:1 - 3:0.1 - 1. The remediation composition for soil contaminated with hexavalent chromium according to the present invention can achieve a leaching rate of 93% for the hexavalent chromium contamination in the soil. At the same time, the composition can reduce more than 95% of the hexavalent chromium in the leaching solution to trivalent chromium with low toxicity, achieving the purpose of completely removing hexavalent chromium from the soil and greatly reducing the material cost of chemical leaching.

The invention discloses a method for detecting heavy metal trivalent antimony ions / hexavalent chromium ions in an environment based on a color developing agent, and belongs to heavy metal ion detection.The method comprises the following steps that a sample to be detected is taken, and acid liquor is added to adjust the pH value of the sample to be detected; adding a color developing agent and a surfactant into the to-be-detected solution, mixing, and standing; after full reaction, the absorbance is measured through a spectrophotometric method, the measured absorbance value of the trivalent antimony ions / hexavalent chromium ions corresponds to the standard curve, and the concentration of the trivalent antimony ions or hexavalent chromium ions in the to-be-measured sample is obtained. Sb < 3 + > / Cr < 6 + > reacts with a color developing agent to generate a stable orange complex, and the stable orange complex has the characteristics of low detection limit and high sensitivity to trivalent antimony ions and hexavalent chromium ions. In addition, the method does not depend on large instruments and equipment, and is simple, efficient and convenient to operate.

The invention relates to a method for curing harmful components in hazardous wastes, which comprises the following steps: uniformly mixing high-silicon iron tailings and blast furnace fly ash, adding the mixed material into chromium-containing waste liquid, stirring, carrying out plate-frame pressure filtration, carrying out pressure filtration again to obtain a mixed material, cutting the mixed material into blocks, drying the cut mixed material, and roasting after treatment to obtain a roasted product; carrying out rapid water cooling on the roasted product, and grinding after water cooling; and performing magnetic separation on the grinding product to obtain iron ore concentrate containing ferrochrome spinel and low-chromium tailings. According to the method, solid waste high-silicon iron tailings and blast furnace fly ash generated by iron and steel enterprises are used as curing agents, curing of heavy metal chromium in the chromium-containing sludge is achieved, the leaching rate of hexavalent chromium and total chromium in the obtained product is far lower than the standard limit value, harmless treatment of the chromium-containing sludge can be achieved, and the method is suitable for industrial production. The obtained ferrochrome spinel can be recovered through magnetic separation, and the generated low-chromium tailings can be directly subjected to landfill treatment or used as building materials.

The invention relates to the field of rolled copper foil preparation, in particular to rolled copper foil and a surface treatment process thereof. According to the method, the process is optimized, and toxic hexavalent chromium electroplating is replaced by optimizing the passivation step and electroplating the Zn-Ni-Mo alloy layer, so that the safety and environmental friendliness are improved, meanwhile, the heat resistance and oxidation resistance of the rolled copper foil are improved, and the requirements of industrial manufacturing are met.

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.