1756 results about "Precious metal" patented technology

The invention discloses a carbon nitride-based composite material as well as a preparation method and application thereof. The carbon nitride-based composite material comprises a non-metal doped carbon nitride carrier and a noble metal, wherein the noble metal exists in the carrier in an element doping form and / or is loaded on the carrier in an oxide form; the precious metal is one or more of Pt, Pd, Au and Ru, and the nonmetal is one or more of P, S and I. According to the carbon nitride composite material disclosed by the invention, noble metal is utilized to modify carbon nitride, the number of surface active sites is increased, the electron and chemical structures of an active center are adjusted, and meanwhile, generation and migration of photo-generated charges are promoted. Meanwhile, the surface of the carbon nitride composite material is modified by non-metallic elements, so that adsorption and activation of reactant H2O molecules are effectively promoted. The catalyst disclosed by the invention is simple in preparation process, good in repeatability and easy for large-scale production.

The invention discloses a high-bismuth slag and precious lead co-processing and efficient recycling method, and belongs to the technical field of non-ferrous metallurgy. High-bismuth slag and precious lead are mixed to obtain impurity-removed precious lead through impurity removal processes such as plug-blow antimony removal, liquation copper removal and tellurium removal by adding agents, and the impurity-removed precious lead is subjected to an oxidation refining process to obtain gold-silver alloy to recover precious metal. Bismuth and lead are similar, silver can be infinitely dissolved in a molten state, and the silver trapping agent has good silver trapping capacity. The high-bismuth slag and the precious lead are mixed to greatly reduce the temperature of a system, volatilization and unknown loss of metal such as Ag are reduced, energy consumption is remarkably reduced, the production cost is reduced, the recovery rate of metal such as bismuth, antimony and silver is increased, and the production efficiency is improved. The obtained molten slag is used for smelting high-bismuth slag, the obtained soot is used for smelting crude antimony, and efficient cyclic utilization of rare and precious metal resources is achieved.

The invention discloses a coating and a method for recovering precious metals in a physical vapor deposition process. The coating mainly comprises a silver coating positioned on the lower layer and an organic silicon modified layer positioned on the surface of the silver coating. Before precious metal is recycled, the coating is prepared on the surface of the position where precious metal needs to be recycled in the physical vapor deposition process, after physical vapor deposition is completed, an adhesive tape is adopted to be pasted to the surface of the coating, and then the precious metal is stripped from the surface of the coating in a mode of tearing the adhesive tape; or scraping the surface of the coating by adopting a tool, so that the noble metal is stripped from the surface of the coating, and stripped noble metal chips are collected; and finally, the adhesive tape with the precious metal or the collected precious metal scraps are heated, and the precious metal is recycled from a heating product. According to the method, efficient stripping and efficient recycling of the precious metal can be achieved, the coating has no influence on physical vapor deposition equipment and the technological process, and the method is simple in technology, high in operability, environmentally friendly, free of pollution and high in economical efficiency when the precious metal is recycled and can be applied to the recycling process of the precious metal on a large scale.

The invention relates to the technical field of precious metal recovery, in particular to a process for separating precious metal from copper-nickel smelting waste, which comprises the following steps: crushing and grading the waste, adding a sulfuric acid solution containing etidronic acid, leaching, and washing, drying and crushing filter residues to obtain a pretreated material; mixing the pretreated material with a sodium peroxide-sodium carbonate composite flux, roasting, leaching with water, and filtering to obtain a filter residue B; adding a leaching agent containing hydrochloric acid, sodium chlorate and 1, 2-cyclohexanediamine tetraacetic acid into the filter residue B according to the ratio of 1: 3-1: 5, and filtering to obtain filtrate C and filter residue C; adjusting the pH value of the filtrate C to 1.5-2.5, adding an ethanol solution of sodium N, N-diethyldithiocarbamate, precipitating, washing and calcining to obtain sponge palladium; adding ammonium chloride into the filtrate D, precipitating and calcining to obtain sponge platinum; and leaching the filter residue C by using a hydrochloric acid-chloroauric acid mixed solution containing diphenylthiourea, and replacing and calcining zinc powder to obtain crude gold. According to the process, the leaching rates of platinum, palladium and gold and the product purity are greatly improved; flux and reagent systems are optimized, consumption and energy consumption are reduced, waste liquid treatment is matched for up-to-standard discharge, and efficient resource recovery and environment-friendly cooperation are achieved.

This invention belongs to the field of high-value utilization technology of biomass resources, and discloses a method for catalyzing the depolymerization of lignin into phenolic compounds using a RuNiZn / Nb2O5 catalyst. The method includes: uniformly mixing the RuNiZn / Nb2O5 catalyst, lignin-containing biomass feedstock, and water; stirring under hydrogen atmosphere to carry out the depolymerization reaction; after the reaction, cooling to room temperature and performing solid-liquid separation; evaporating the solvent to obtain the hydrogenated depolymerization product containing monophenols. In this invention, the RuNiZn / Nb2O5 catalyst employs a technique of replacing precious metals with various non-precious metals, which improves the catalyst's reactivity and reduces the amount of precious metals used. This increases the yield of lignin depolymerization products, provides milder depolymerization reaction conditions, and ultimately significantly reduces the catalyst preparation cost and the energy cost of the lignin depolymerization process.

The invention discloses a method for recovering precious metal from refining wastewater, and relates to the technical field of wastewater resourceful treatment. Comprising the following steps: adding a porous carbon-based composite material into the acidic silver-containing refining wastewater, and stirring for adsorption to obtain an adsorption solution; the porous carbon-based composite material adsorbing the silver ions is recycled in a filtering or centrifugal separation mode; the porous carbon-based composite material adsorbing the silver ions makes contact with a desorption agent, desorption treatment is conducted, and a regenerated porous carbon-based composite material and a silver-containing desorption solution are obtained through separation; and a reducing agent is added into the silver-containing desorption solution, and silver ions are reduced into elemental silver to be recycled. The precious metal silver in the refining wastewater is recovered by adopting an adsorption method, and the recovery rate of the silver is relatively high.

The invention discloses a zeolite / silver / copper ternary inorganic nano antibacterial and antiviral material as well as a preparation method and application thereof. The preparation method comprises the following steps: preparing a mixed solution of a template agent and an anchoring agent, loading a metal precursor, adding a silicon source, performing hydrothermal crystallization and performing post-treatment. According to the zeolite / silver / copper ternary inorganic nano antibacterial and antiviral material disclosed by the invention, Ag-Cu bimetallic nanoparticles are formed by introducing copper nitrate and silver together, so that the catalytic activity, selectivity and stability of the zeolite / silver / copper ternary inorganic nano antibacterial and antiviral material are remarkably enhanced, and the dosage of noble metal silver can be reduced.

The invention provides a method for recovering platinum group metal from a waste automobile exhaust purification catalyst, and belongs to the field of precious metal recovery. The method comprises the following steps: carrying out crushing and impurity removal pretreatment on the waste catalyst to obtain solid residues; mixing the obtained solid slag with alkali liquor, and performing hot-pressing activation to obtain active slag; leaching the active slag by using an acid leaching system of hydrochloric acid-hydrogen peroxide-sodium chloride to obtain a leaching solution enriched with platinum group metals; adjusting the acidity of the leachate, adding a first adsorption material, selectively adsorbing platinum and palladium, and separating supernate and a platinum / palladium enrichment material; adjusting the acidity of the supernate, adding a second adsorption material, selectively adsorbing rhodium, carrying out solid-liquid separation, and collecting a rhodium enrichment material; respectively eluting and refining the platinum / palladium enrichment material and the rhodium enrichment material, and recovering platinum, palladium and rhodium; through the optimally designed recovery method of alkaline hot-pressing activation-mild acidic directional leaching-two-stage magnetic adsorption separation, efficient recovery of platinum, palladium and rhodium in the waste automobile exhaust catalyst is realized.

The invention relates to the technical field of biological aviation kerosene, and discloses a process for preparing biological aviation kerosene from waste grease. The method comprises the following steps: introducing waste oil into a hydrofining reactor, introducing hydrogen, carrying out a hydrodeoxygenation reaction under the catalysis of a hydrogenation catalyst, carrying out a reaction on the obtained hydrodeoxygenated oil in an isomerization pour point depressing reactor, and finally carrying out isomerization hot high-pressure separation treatment, isomerization cold high-pressure separation treatment and rectification tower segmentation to obtain the biological aviation kerosene. The specific surface area of a carbon matrix of the hydrogenation catalyst is large, the void structure is rich, a large number of Ni-Mo-P active catalytic centers can be exposed, precious metals such as platinum and ruthenium do not need to be added, the hydrodeoxygenation reaction efficiency of waste oil and fat is remarkably improved, the mass fraction of branched paraffin and cycloparaffin in biological aviation fuel is high, and the combustion performance is better.

The utility model relates to the technical field of automobile parts, in particular to a three-way catalyst shell with a spiral guide plate, which comprises a three-way catalyst shell body, a reaction chamber is arranged in the three-way catalyst shell body, an air inlet and an air outlet are arranged at two ends of the three-way catalyst shell body, and the air inlet and the air outlet are communicated with the reaction chamber. An air guide structure communicated with the air inlet is arranged in the three-way catalyst shell body and comprises a flow guide column, a spiral flow guide plate and an air distribution plate, the spiral flow guide plate and the air distribution plate are sequentially, coaxially and fixedly connected to the flow guide column in the air inlet direction, and the outer wall of the spiral flow guide plate and the outer wall of the air distribution plate are closely attached to the inner wall of the three-way catalyst shell body. And a plurality of flow guide grooves are formed in the gas distribution plate, so that the problems that the performance of a traditional three-way catalyst is improved by improving the content of precious metal, and the manufacturing cost is sharply increased due to the increase of the content of the precious metal are solved.

The present disclosure is directed to a process that includes receiving a refractory precious metal-containing material comprising a preg-robbing material, determining a preg-robbing strength of the preg-robbing material relative to a sorbent, and a preg-robbing capacity after pressure oxidation and / or a preg-robbing capacity in the presence of a blanking agent, and, based on the preg-robbing strength of the preg-robbing material relative to a sorbent and the preg-robbing capacity after pressure oxidation and the preg-robbing capacity in the presence of a blanking agent, directing the refractory precious metal-containing material to a selected one of a plurality of unit processing operations for recovery of the precious metal in the refractory precious metal-containing material.

The invention discloses a multi-process energy consumption dynamic optimization control system for a precious metal processing production line, and relates to the technical field of precious metal processing, and the system comprises a data collection module which is used for collecting energy consumption data, process parameters and material flow data of equipment in real time; the optimization decision module comprises an energy consumption modeling unit and a dynamic optimization unit; the energy consumption modeling unit is used for establishing an energy consumption digital twin model for key equipment on a production line; the dynamic optimization unit is used for receiving and calculating a current optimal process parameter set value and an optimization instruction for adjusting the operation power and rhythm of equipment; and the driving execution module is used for realizing collaborative energy consumption optimization control of multiple processes. The method has the advantages that accurate energy consumption perception is achieved by constructing the energy consumption digital twinborn model, meanwhile, order merging is intelligently decided based on the material flow state and the order delivery time, and double optimization of overall energy efficiency improvement of the production line and comprehensive energy consumption cost is achieved.

The invention discloses a micro-fine particle gold ore normal-pressure alkaline leaching pretreatment method based on sodium percarbonate reinforcement, and belongs to the field of precious metal metallurgy. The method comprises the following steps: adding an oxidizing agent sodium percarbonate in batches under the condition that air is filled into ore pulp, starting to monitor the oxidation potential and the pH value of a reaction system after adding, judging that the reaction reaches the end point when the sudden drop amplitude of the oxidation potential of the ore pulp within one hour is greater than or equal to 30mV and the pH value is increased by 0.3-0.5 unit, and stopping aeration to finish pretreatment; in the segmented oxidation process, the oxidation potential is controlled within the range of + 520 mV to + 550 mV by dynamically adjusting the air charging rate. According to the basic technical scheme, the gold leaching rate reaches 86.01%, the gold leaching rate reaches up to 88.92% through the optimized technical scheme, and the utilization rate of gold ore resources is remarkably increased.

The invention discloses a non-noble metal ORR catalyst and a preparation method thereof, and belongs to the technical field of electro-catalysis. The method comprises the following steps: (1) adding 5, 10, 15, 20-tetra (4-cyanophenyl) porphyrin and nickel salt into an organic solvent, and synthesizing a supramolecular crystal precursor UPC-S7 through solvothermal reaction; (2) carbonizing the supramolecular crystal precursor UPC-S7 in an inert atmosphere to obtain a Ni-coated NC material; (3) oxidizing the Ni-coated NC material in an oxygen-containing atmosphere to obtain a Ni / NiO-coated NC material; and (4) sequentially soaking and etching the Ni / NiO-coated NC material by using a nitric acid solution and an ammonia water solution, and then washing and drying to obtain the non-noble metal ORR catalyst. The prepared catalyst does not contain precious metal such as platinum, the raw material cost is remarkably reduced on the basis of ensuring the ORR activity and stability of the catalyst, and a new scheme is provided for solving the cost bottleneck of a fuel cell.

The invention provides a method for preferentially extracting gold and silver from lead anode slime, and relates to the technical field of precious metal recovery, firstly, silver, antimony and other valuable metals in the lead anode slime are leached into a solution through catalytic oxidation leaching in the presence of a protective agent, and gold is enriched in residues; then, silver is selectively precipitated from the leachate, and silver precipitation residues and a valuable metal solution are obtained; and finally, valuable metals in the solution are recovered by adding a neutralizer and a precipitator, the obtained leaching mother liquor can be returned for leaching after being supplemented with hydrochloric acid, and the valuable metal precipitates are used for recovering antimony and bismuth. The method changes the traditional lead anode slime treatment thinking of first impurity removal and second refining, has the characteristics of high gold and silver direct recovery rate (greater than 99.5%), high reaction speed (total consumed time is less than 1 h), low cost and no generation of waste residue and wastewater, and is expected to solve the problems of long gold and silver recovery process, low direct recovery rate, capital overstock and difficult treatment of arsenic and antimony-containing smoke in the existing lead anode slime treatment method. The method has remarkable economic and environmental benefits and a good application prospect.

The invention provides a method for recovering rhodium in organic residual liquid containing triphenylphosphine / phosphine oxide, and relates to the technical field of precious metal recovery, and the method comprises the following steps: S1, carrying out reduced pressure rectification on the organic residual liquid containing triphenylphosphine / phosphine oxide to remove volatile components until the indexes of the residual liquid meet the feeding requirements of a subsequent process, and collecting light components for independent storage; s2, adding an acidic medium into the organic phase after light component removal, stirring and heating, introducing an oxidizing agent to carry out oxidation-complexation reaction, maintaining reaction conditions until the reaction is complete, standing for phase splitting, and collecting a water phase containing rhodium complex ions; according to the method, a core process combining oxidation-chlorination transfer and anion exchange adsorption is adopted, and key parameters of each process are accurately controlled, so that the rhodium recovery rate is stabilized at 95% or above, the rhodium content in the residual liquid can be reduced to 5 ppm or below, the industrial emission standard is completely met, and compared with the prior art, the resource recovery efficiency is greatly improved, and the cost is reduced. And waste of precious metal resources is effectively reduced.

The invention belongs to the field of electrochemical energy storage, and discloses an electrode suitable for an organic flow battery and a preparation method of the electrode. The electrode comprises a porous electrode substrate and an amino functional group loaded on the surface of a pore channel, and the electrode substrate is prepared by taking mixed powder of noble metal, rare earth metal and titanium alloy as a raw material. A selective laser melting process is adopted to prepare a porous electrode substrate, and then an electrostatic self-assembly process is adopted to load amino functional groups on the surfaces of pore channels. The electrode has a porous structure with a high specific surface area, and can provide sufficient reaction sites for electrochemical reaction. Meanwhile, the loaded amino functional group can enhance the activity and stability of positive and negative electrode electrochemical substances. The electrode base material comprises a noble metal with catalytic activity and a rare earth metal, and an active rare earth oxide layer doped with a noble metal oxide can be formed on the surface of the electrode after printing. According to the electrode, the energy efficiency of the organic flow battery can be improved, and the stable cycle index and the service life are prolonged on the basis of maintaining the energy efficiency.

Herein is described a composite material, the composite material comprising composite 5 particles comprising particles of a mesoporous carbon support material having dispersed on their surfaces noble metal nanoparticles and / or noble metal-M alloy nanoparticles and optionally particles of the elemental metal M or metal oxide MOy, wherein y is >0 to a stoichiometric value of the metal oxide, wherein M is a less noble metal than the noble metal, wherein the composite particles have a BJH average pore diameter of from 2 to 0 50 nm and a particle size D90, as measured by laser diffraction and volume distribution, of 10 µm or less.

The application relates to the technical field of image recognition, in particular to a precious metal quality defect detection method based on image recognition; a gray scale characteristic value of a pixel point is obtained according to the gray scale characteristics of the same pixel point in all detection images; a brightness deviation degree of the pixel point is obtained according to the difference characteristics of the gray scale characteristic values of the pixel point and multiple normal precious metals at the same position; different suspected defect regions are obtained according to the brightness deviation degrees of all the pixel points; and a defect confidence of the suspected defect region is obtained according to the distribution characteristics of the gray scale characteristic values and the gradient amplitude distribution characteristics of the pixel points in the suspected defect region. The application detects defects of the precious metal to be detected according to the defect confidence of the suspected defect region, and the accuracy of the surface defect detection of the precious metal is improved.

The invention belongs to the technical field of energy chemical industry and catalysis, and discloses a preparation method for preparing synthesis gas through iron-catalyzed methane dry reforming. According to the method, gamma-aluminum oxide is taken as a carrier, ferric nitrate is loaded by adopting an equivalent-volume impregnation method, an iron oxide catalyst is formed through drying and roasting, and metal iron active sites with high dispersity are obtained through hydrogen reduction. The reaction is carried out in a fixed bed reactor, the reaction temperature is controlled to be 650-700 DEG C, methane and carbon dioxide are mixed according to the volume ratio of 1: 1 and introduced into the reactor under the normal pressure condition, and efficient dry reforming is realized to generate synthesis gas. According to the method, the methane conversion rate can reach 85% or above, and the carbon dioxide conversion rate can reach 90% or above. Compared with the existing noble metal or nickel-based catalytic system, the catalyst disclosed by the invention has the advantages of cheap raw materials, simple and convenient preparation process, excellent carbon deposition resistance, capability of keeping high activity and stability at lower temperature, low energy consumption, low cost, strong environmental protection property and suitability for industrial amplification.

The invention relates to the technical field of precious metal recovery, in particular to a method and system for recovering gold, silver, palladium and platinum from silver anode slime. S2, palladium precipitation: adding a potassium-magnesium mixture and sodium chlorate into the pre-impregnation liquid obtained in S1 to obtain palladium precipitation residues and platinum precipitation liquid; s3, separating gold; s4, platinum and palladium precipitation: adding a potassium-magnesium mixture and sodium chlorate into the gold separation liquid obtained in S3 to obtain platinum and palladium precipitation residues and platinum and palladium precipitation post-liquid; s5, gold is reduced; s6, platinum and palladium separation, wherein hydroxylamine hydrochloride is added into the platinum and palladium precipitation residues obtained in the step S4, and palladium separation liquid and platinum precipitation residues are obtained; 7, platinum purification, wherein hydroxylamine hydrochloride is added into the platinum precipitation residues obtained in the step 6, and platinum separation liquid is obtained; s8, carrying out primary palladium deposition; s9, carrying out secondary palladium deposition; and S10, palladium is reduced. The recovery rate of palladium is 99% or above, the recovery rate of platinum is 99% or above, the purity of platinum is 99.9%, the purity of palladium is 99.95%, the recovery rate of silver is 98.5% or above, and the recovery rate of gold is 99% or above.

The invention discloses an AgBr-loaded ZnO material, a preparation method of the AgBr-loaded ZnO material and an isopropanol sensor. The method comprises the following steps: firstly, dissolving glucose and urea in deionized water, uniformly stirring, and then adding a zinc source; carrying out hydrothermal reaction on the obtained solution, and firing a product to obtain a ZnO material; and dispersing a proper amount of ZnO powder into deionized water, sequentially adding a bromine source solution and a silver source solution, stirring, collecting a product, washing, and drying to obtain the AgBr-loaded ZnO material. According to the method, the concentration of oxygen adsorbed on the surface of ZnO is remarkably improved by utilizing the overflow effect of noble metal Ag and photoelectron transfer between AgBr and ZnO, so that the chemical reaction between the oxygen and isopropanol is promoted. The prepared AgBr-loaded ZnO material has the characteristics of high sensitivity, rapid response, low detection lower limit, good selectivity and the like for isopropanol gas at a relatively low working temperature.

A method for recovering platinum group precious metal in a silicon carbide DPF catalyst comprises the steps that S1, smelting treatment is conducted, specifically, the silicon carbide DPF catalyst is crushed and then mixed with a smelting agent in a layered mode, a smelting reaction is conducted at the high temperature, and the smelting agent is composed of sodium carbonate and sodium peroxide; s2, leaching and separation are conducted, specifically, after the smelting product obtained in the step S1 is cooled, acid leaching treatment is conducted through hydrochloric acid, leaching liquid containing platinum group precious metal and residues are obtained through filtering separation, the residues are washed, and washing liquid is added into main leaching liquid; and S3, precious metal enrichment is conducted, specifically, the leachate obtained in the step S2 is enriched through a chemical precipitation method, the obtained precipitate is dissolved with aqua regia, and a platinum-palladium chloride mixed solution is obtained. The method is high in recovery rate, and under the optimal condition, the recovery rate of platinum can reach 91% or above, and the recovery rate of palladium can reach 96% or above; the process is simple, the cost is controllable, the used smelting agent is a common chemical raw material, and the cost is low.

The present invention relates to the technical field of catalysts, and specifically relates to a high-activity cerium-zirconium composite oxide, and a preparation method therefor and a catalytic application thereof. The cerium-zirconium composite oxide has a general chemical formula of CexZryTzO2-αRδ, wherein, in terms of molar content, 0<x≤0.95, 0<y≤0.95, 0<z<0.3, x, y, and z satisfy x+y+z=1, 0≤α≤0.2, and 0≤δ≤0.1. The surface of the cerium-zirconium composite oxide contains adsorbed oxygen species, wherein an XPS peak intensity ratio of adsorbed oxygen to lattice oxygen, i.e., IOads / (IOads+IOlatt), is 0.3-0.8. In the present invention, the generation of more adsorbed oxygen species on the surface of the cerium-zirconium composite oxide is induced by constructing a non-uniform rare earth element doping structure and a grain boundary defect structure, and regulating and controlling the surface acidity and alkalinity. The adsorbed oxygen species on the surface can directly act as active oxygen to participate in a low-temperature catalytic reaction process, thereby promoting the activation of free O2, improving oxygen mobility and low-temperature co-catalytic activity, inhibiting the migration, agglomeration and growth of precious metals at high temperatures, and synergistically improving the high-temperature dispersity and catalytic activity of precious metals.

The invention discloses a method for preparing a carbon-coated cobalt-cerium composite material by using rapid Joule heat, and belongs to the technical field of catalytic materials and hydrogen production by electrolyzing water. The method comprises the following steps: dissolving a cobalt source and a cerium source in a solvent to obtain a mixed metal salt precursor solution, and then uniformly dipping or dropwise adding the mixed metal salt precursor solution onto a cellulose-based porous carbon source precursor to obtain a supported precursor; and finally, placing the load type precursor at two ends of an electrode of a Joule thermal reaction device, and under a vacuum condition, applying instantaneous current to carry out Joule thermal shock treatment so as to prepare the CoCe-C composite material. The preparation process is extremely simple, the energy consumption is extremely low, expensive precious metal and complex equipment are not needed, the obtained CoCe-C material serves as an anode catalyst to be applied to a hydrazine oxidation auxiliary water electrolysis system, the excellent catalytic activity and stability are shown, the voltage of an electrolytic bath can be remarkably reduced, low-energy-consumption, efficient and safe hydrogen production is achieved, and the method is suitable for industrial production. Wide industrial application prospects are realized.

The invention belongs to the technical field of precious metal recovery and resource cyclic utilization, and particularly discloses a thermal driving interface micro-droplet mediated precious metal selective recovery method. The method comprises the following steps: firstly, mixing a to-be-treated solution containing noble metal ions with an auxiliary organic phase to construct an organic-inorganic interface system; then heating the organic-inorganic interface system to induce generation of micro-nano-scale micro-droplets at the phase interface, and promoting reduction reaction of noble metal ions to obtain noble metal precipitates; and separating the precious metal precipitate to finish selective recovery of the precious metal. According to the method, precious metal ions are efficiently reduced into simple substances by using high-activity reducing substances generated on the surfaces of the micro-droplets, and selective recovery of precious metal is realized by virtue of a specific reduction reaction threshold value of a system. The self physical and chemical characteristics of the system can also be utilized to promote the reduction products to spontaneously aggregate and grow into large-size particles, so that the subsequent separation is facilitated. The method has the advantages of no need of adding an external reducing agent, simple operation, mild conditions and good selectivity.

The invention discloses a preparation method and application of an electrospun nanofiber membrane-based flexible SERS (Surface Enhanced Raman Scattering) substrate, and belongs to the field of preparation of SERS substrates. The preparation method comprises the following steps: firstly, preparing a polymer nanofiber membrane by adopting an electrostatic spinning method, and then depositing noble metal nanoparticles on the surface of the electrospinning polymer nanofiber membrane by adopting a magnetron sputtering technology, so as to obtain the noble metal nanoparticle and polymer nanofiber membrane flexible SERS (Surface Enhanced Raman Scattering) substrate. According to the present invention, the problems that the SERS substrate cannot be accurately controlled and cannot be continuously produced are solved, the preparation method has advantages of simpleness, high efficiency, no pollution, low cost and large-scale manufacturing compared with the existing preparation method, the substrate has characteristics of large specific surface area, high density hot spot distribution, good stability and adjustable size structure, and the trace detection of the pesticide residue on the irregular surface can be achieved.

The utility model discloses a precious metal waste recycling device which comprises a box body, a stirring shaft is rotatably connected to the interior of the box body, stirring rods are fixedly connected to the outer side of the stirring shaft at equal intervals, a fixing frame is fixedly connected to one side of the box body, and a motor is fixedly connected to the outer side of the fixing frame. According to the precious metal waste recycling device, the box body, the transmission shaft, the connecting rod, the push rod, the sliding frame, the sliding rod, the fixed rod, the connecting rod, the filter frame and the cover plate are arranged, so that the waste is in full contact with a dissolving solution, the dissolving efficiency of precious metal is improved, the recycling time is shortened, and the cost is reduced. The filtering frame can block and collect waste residues which cannot be dissolved; and by arranging a second bevel gear, a first bevel gear, a stirring shaft and a stirring rod, the function of stirring the dissolved solution is achieved, the dissolving efficiency of the precious metal is further improved, and recycling of the precious metal is facilitated.

This invention relates to a method for the recovery of metal from a material comprising: contacting a material with a first reagent comprising a thiocarbonyl group and a second reagent under various conditions. The metal may be a base metal, a precious metal, or a combination thereof. The conditions include, but are not limited to, recovery in the presence of a microbe; optimal material size and / or shape; geolocation parameters; elemental sulfur; added pyrite; or a combination thereof.

The invention provides a reductive amination catalyst as well as a preparation method and application thereof, and belongs to the field of catalysis. The invention provides a reductive amination catalyst. The reductive amination catalyst comprises layered Al2O3 and an alloy loaded on the surface of the layered Al2O3, the alloy comprises a nickel element and a non-noble metal element; the non-noble metal elements comprise one or more of Cu, Mg, Ca, Co and Zn. The nickel element and the selected non-noble metal element are alloyed to adjust the charge structure of a metal site, so that excessive hydrogenation of HMF is inhibited during catalysis, it is ensured that only the aldehyde group of HMF is subjected to a reductive amination reaction, and therefore the selectivity of HMFA is improved.