18 results about "Tollens' reagent" patented technology

The invention belongs to the technical field of rare and precious metal recovery, and particularly relates to a method for recovering metallic silver from waste crystalline silicon battery pieces, which comprises the following steps: (1) putting the waste crystalline silicon battery pieces into an inorganic alkali aqueous solution for soaking reaction to obtain an aluminum-containing solution and dealuminized crystalline silicon pieces; (2) adding the dealuminized crystal silicon wafer into a mixed solution of organic acid and hydrogen peroxide for soaking reaction, filtering and washing to respectively obtain silver-containing filtrate and a silver-removed silicon wafer; (3) carrying out chlorination precipitation reaction on the silver-containing filtrate and a chlorine source, filtering and drying to obtain silver chloride powder; (4) adding silver chloride powder into an ammonia water solution, heating and stirring to completely dissolve silver chloride to obtain a silver-ammonia solution; (5) adding PVP (Polyvinyl Pyrrolidone) into the silver-ammonia solution, heating and stirring until the PVP is completely dissolved, adding ascorbic acid, and carrying out reduction reaction at room temperature to obtain metal silver powder precipitate; and filtering, washing and drying the precipitate to obtain the spherical silver powder. According to the method, the silver recovery efficiency is high, the spherical nanoscale silver powder can be prepared, and the purity is high.

The invention relates to a silver recovery technology, in particular to a method for preparing high-purity silver powder by recovering silver from retired photovoltaic module cells, which comprises the procedures of pretreatment, leaching treatment, suction filtration treatment, silver precipitation treatment, silver chloride precipitation and purification treatment, silver ammonia solution reduction and the like. The method comprises the following steps: by taking a disassembled retired photovoltaic module battery piece as a raw material, firstly, removing dust on the surface of the battery piece and metal impurities partially attached to the surface of the battery piece through pretreatment, leaching the cleaned battery piece by using a nitric acid solution, carrying out suction filtration by using a suction filtration machine, and separating to obtain silicon slag and a silver nitrate solution; the method comprises the following steps: adding a chlorinating agent into a silver nitrate solution, reacting to generate silver chloride precipitate, dissolving the separated silver chloride precipitate by using ammonia water to form a silver-ammonia solution, and finally adding a reducing agent into the silver-ammonia solution to obtain high-purity silver powder and ammonia water; compared with the conventional technology, the method for recovering silver has the advantages of low cost, no wastewater generation and simpler process, and meets the requirements of economy, high efficiency and environmental protection.

The utility model discloses a solution purification device for a chemical laboratory. The solution purification device comprises a mounting plate and a base connected with the bottom of the mounting plate, the mounting plate is connected with an adding tank, the bottom of the adding tank is connected with a control valve, and the other side of the mounting plate is connected with a swinging part; according to the silver-ammonia solution preparation device, the accuracy of silver-ammonia solution preparation can be effectively improved, ammonia water and silver oxide can fully react through a continuous shaking effect, and the silver-ammonia solution preparation device has the advantages that the accuracy of silver-ammonia solution preparation is improved; therefore, silver oxide precipitates and other incompletely reacted chemical components are prevented from remaining in the prepared solution, and the effect of purifying the silver-ammonia solution by the device is achieved.

The invention discloses a catechin silver nano antibacterial particle as well as a preparation method and application thereof, and belongs to the technical field of antibacterial materials. The silver catechin nano antibacterial particles disclosed by the invention are Ct-Ag NPs, and the silver catechin nano antibacterial particles are Ct-Ag NPs; the Ct-Ag NPs is of a spherical structure; the average particle size of the Ct-Ag NPs ranges from 142 nm to 162 nm; ag in the Ct-Ag NPs is uniformly dispersed in catechin to form a core-shell structure. The preparation method of the silver catechin nano antibacterial particles comprises the following steps: weighing catechin, and dissolving the catechin in a sodium hydroxide solution to obtain a catechin sodium salt solution; adding the silver nitrate solution into the ammonia water solution to obtain a silver ammonia solution; and under the conditions of stirring and ice bath, adding the catechin sodium salt solution into the silver ammonia solution, centrifuging, cleaning with trichloromethane, and drying to obtain the Ct-Ag NPs. The Ct-Ag NPs provided by the invention has a core-shell structure, and the quorum sensing inhibitor shell Ct can effectively reduce the generation of biological membranes, so that bacteria are more sensitive, and the bactericidal effect of continuously releasing Ag < + > is effectively improved.

The application provides a silver cluster zeolite and a preparation method and application thereof, and belongs to the technical field of bactericides. A sodium hydroxide solution and sodium metaaluminate are mixed, then silica sol is added dropwise, and then aging treatment is performed to obtain an aged mixture; silver nitrate, ammonia water and water are mixed to obtain a silver ammonia solution; the silver ammonia solution is added dropwise into the aged mixture, and microwave in-situ reaction is performed to obtain the silver cluster zeolite. The application performs high-temperature rapid synthesis of ZSM-5 zeolite by means of pre-synthesis of seeds and microwave in-situ reaction, so that the synthesis speed of the zeolite and the generation rate of silver nanoparticles are approximately equal, the silver nanoparticles and the zeolite framework are synchronously synthesized, the size difference of the formed silver nanoparticles is small, and the silver nanoparticles are uniformly distributed in the framework of the zeolite.

The application relates to the technical field of silver powder preparation, in particular to a high-dispersion and wide-distribution silver powder preparation method and device, wherein the preparation device comprises a guide rail, a flushing system, an oven and a material mixing tank composed of an upper tank body and a movable lower seat body; the movable lower seat body can be separated from the upper tank body and sequentially moved to a flushing station below the flushing system along the guide rail to be flushed and to a heating station below the oven to be dried; a movable cleaning assembly is further connected to the guide rail and moved to the exact position below the upper tank body to flush the inside of the upper tank body. The material mixing tank composed of the upper tank body and the movable lower seat body can simultaneously complete the proportioning of silver amine solution A, dispersant solution B, surface active agent solution C and reducing liquid D, so that the work efficiency is greatly improved.

The invention discloses a preparation method of ultralow-porosity silver-coated copper powder, and belongs to the technical field of metal powder surface modification. The preparation method comprises the following steps: adding copper powder into a mixed solution containing NaOH, SDS, Tween 80 and sodium citrate, and carrying out ultrasonic treatment; immersing the filtered solid into a H2SO4 solution for ultrasonic treatment, and secondarily dispersing the filtered solid into a NaOH solution for ultrasonic treatment to obtain an activated copper powder suspension; and the activated copper powder suspension is added into a mixed solution of sodium potassium tartrate tetrahydrate and erythrosine B, then the mixture is placed under ultrasonic and ultraviolet irradiation, finally, a silver ammonia solution is added for a reaction, and after the reaction is finished, washing, centrifugal separation and drying are conducted to obtain the ultralow-porosity silver-coated copper powder. The obtained ultralow-porosity silver-coated copper powder coating is low in porosity, high in bonding strength, high in oxidation resistance, high in coating uniformity and good in conductivity.

The invention relates to silver-coated copper powder and a preparation method thereof.The preparation method comprises the following steps that S1, a dispersing agent, water, a first reducing agent and a first pH regulator are mixed, a mixed solution is obtained and then heated, a copper source water solution is dropwise added, centrifuging, washing and drying are conducted after reaction, and copper powder is obtained; s2, mixing copper powder, water and a second pH regulator to obtain a copper particle dispersion system; s3, mixing a silver source, water, ammonia water and a third pH regulator to obtain a silver-ammonia solution; and S4, the silver-ammonia solution, the copper particle dispersion system and the second reducing agent aqueous solution are mixed for a reaction, and after the reaction is completed, centrifugation, washing and drying are conducted to obtain the silver-coated copper powder. Compared with the prior art, the high conductivity of the silver-coated copper powder is achieved through the low silver coating amount, no toxic solvent participates in, the steps are simple, the cost is low, and environment friendliness is achieved.

The invention belongs to the technical field of conductive materials, and particularly discloses spherical silver-coated copper powder with high oxidation resistance and a preparation method of the spherical silver-coated copper powder. The preparation method comprises the following steps that copper powder is subjected to surface pretreatment and then evenly mixed with deionized water, a dispersing agent and a complexing agent, and copper powder dispersion liquid is obtained; adding the silver-ammonia solution A into the copper powder dispersion liquid for reaction, and then carrying out solid-liquid separation, washing and drying to obtain prefabricated silver-coated copper powder; uniformly mixing the prefabricated silver-coated copper powder with deionized water, a dispersing agent and a complexing agent to obtain prefabricated silver-coated copper powder dispersion liquid; the method comprises the following steps: uniformly mixing a silver-ammonia solution B with a prefabricated silver-coated copper powder dispersion liquid to obtain a mixture; and adding a reducing agent solution into the mixture, carrying out reduction reaction, and carrying out solid-liquid separation, washing and drying to obtain the silver-coated copper powder. The silver-coated copper powder has good compactness and uniformity, only a small amount of free silver is distributed on the surface of the prepared silver-coated copper powder, and obvious agglomeration is avoided.

The utility model discloses teaching experiment equipment, which is used for an ethanol catalytic oxidation reaction and acetaldehyde inspection, and comprises an injector used for accommodating ethanol liquid; the heating device comprises a heating core, the heating core is inserted into the glass tube, and a copper piece is arranged on the heating core; the ventilation device is connected with the two balls and is used for introducing air into the glass tube; the first test tube with the branch is connected with the glass tube and is filled with a newly prepared copper hydroxide solution; and the second test tube with the branch contains a silver-ammonia solution. In the teaching experiment equipment, the ethanol liquid, the copper piece and oxygen in the air can react to generate acetaldehyde, the acetaldehyde reacts with the medicine in the test tube with the branch tube to respectively generate brick-red cuprous oxide sediment and a bright silver mirror, and the heating core is inserted into the glass tube, so that the safety is higher; by observing brick-red cuprous oxide precipitate and generation of a silver mirror, acetaldehyde generated by reaction in the glass tube can be accurately confirmed.

The invention relates to the technical field of silver powder preparation, in particular to a high-dispersion and wide-distribution silver powder preparation method and device, and the preparation device comprises a guide rail, a flushing system, a drying oven and an ingredient mixing tank composed of an upper tank body and a movable lower seat body. The movable lower seat body can be separated from the upper tank body and can move to a flushing station below a flushing system for flushing and move to a heating station below a drying oven for drying in sequence along a guide rail, and a movable cleaning assembly is further connected to the guide rail; the movable cleaning assembly moves to the position under the upper tank body along the guide rail to wash the interior of the upper tank body. According to the invention, the proportioning of a silver-ammonia solution A, a dispersant solution B, a surfactant solution C and a reducing solution D can be completed at the same time through the proportioning and mixing tank consisting of the upper tank body and the movable lower seat body, so that the working efficiency is greatly improved.

The present application belongs to the field of environmental pollution detection and treatment technology, and particularly relates to a preparation method of AgCl / Ag composite material and application of the AgCl / Ag composite material in detection and degradation of rhodamine B. The present application provides a SERS substrate based on the AgCl / Ag composite material, which realizes SERS spectrum detection and quantitative analysis of rhodamine B. Silver nitrate and hydrochloric acid are reacted to generate AgCl, polyvinylpyrrolidone is used for dispersion, Ag nanoparticles are grown on the surface of AgCl by introducing silver ammine solution to form a core-shell structure, and the Raman signal is significantly enhanced. In view of the great harm of rhodamine B to water environment, the present application further coats tetrabutyl titanate on the surface of AgCl / Ag, hydrolyzes and calcines to form a TiO2 shell layer, constructs an AgCl / Ag / TiO2 composite material, and realizes efficient degradation of rhodamine B.

The present application relates to a kind of preparation method of catechol-furfuryl resin nanosphere with surface having lychee-like concave-convex structure capable of loading silver nanoparticles, belong to biomass-based nanomaterial preparation technology related field, comprising: (1) catechol, ammonia is added to the mixed solution of ethanol and water and mixed uniformly, after adding appropriate amount of furfuryl, hydrothermal reaction is carried out, and ABR is obtained after centrifugal drying (hereinafter referred to as ABR);(2) different concentrations of silver ammonia solution are added to the surface of ABR to load silver, and form ABR@Ag composite material.By adjusting the molar ratio of furfuryl and catechol and the addition amount of ammonia in step (1), the particle size and surface roughness of ABR resin ball can be controlled, and the surface pore size and specific surface area of ABR can be controlled, and preferably a resin ball with lychee-like concave-convex structure on the surface can be obtained, which shows excellent performance in subsequent silver nanoparticle loading (loading capacity is nearly 30%), and has potential application value.

The invention discloses a preparation method of flake silver powder, which comprises the following steps: adding ammonia water into a silver nitrate solution to obtain a silver ammonia solution; adding stearic acid into the silver-ammonia solution to obtain a first mixed solution; and the first mixed solution and a hydroxylamine sulfate solution are added into a polyvinyl pyrrolidone solution containing copper nitrate, a primary stirring reaction is carried out, lauric acid is added for a secondary stirring reaction, cleaning, drying and powder mixing and ball milling are carried out, and then the flake silver powder is obtained. According to the invention, stearic acid and lauric acid are used for dual coating, copper nitrate is used for particle size adjustment, and stirring and ball-milling modes of a refining process are adopted, so that nucleation, growth and morphology of the flake silver powder are regulated and controlled, and the influence of environmental fluctuation on the quality of the silver powder is overcome; the prepared flake silver powder is high in morphology regularity, concentrated in particle size distribution, excellent in dispersity and small in batch difference, and then the tap density and the surface activity of the silver powder are improved.

The invention discloses a preparation method of flake silver powder. Relates to the field of silver powder preparation. The preparation method of the flaky silver powder comprises the following steps that S1, a dispersing agent, a silver-ammonia solution and a first reducing agent are mixed, and first reaction liquid is obtained through first reaction; s2, mixing the first reaction liquid with a second reducing agent, and carrying out a second reaction under the condition that the pH value is 5.0-6.5 to obtain a second reaction liquid; and S3, mixing the second reaction liquid with a flaky guiding agent, carrying out third reaction under the condition that the pH value is 6.0-8.0, and then carrying out fourth reaction under the condition that the pH value is 5.0-6.7 to obtain the flaky silver powder, the reducibility of the second reducing agent is greater than that of the first reducing agent; the reducibility of the second reducing agent is greater than that of the first reducing agent. The method can efficiently and stably prepare the product with good dispersibility, controllable thickness-diameter ratio and surface roughness lt; and 5% of stable flake silver powder.

The invention discloses a preparation method of silver-plated copper powder based on high-activity replacement, and belongs to the technical field of metal surface treatment. The copper powder is subjected to alkali washing, acid washing and water washing and then subjected to ultrasonic treatment for 15-25 min at the temperature of 60-70 DEG C with a 35-45 vol% ethanol water solution. The surface activated copper powder is dispersed in a solution containing 10-30 g / L of a complexing main agent and 8-15 g / L of a complexing auxiliary agent, EDTA disodium is preferably selected as the complexing main agent, and potassium sodium tartrate is preferably selected as the complexing auxiliary agent. A silver-ammonia solution with the Ag < + > concentration being 8-12 g / L and the ammonia water concentration being 2.5-4.0 mol / L is dropwise added into a reaction system at the temperature of 35-45 DEG C at the speed of 0.2-1.0 mL / min; and after the reaction is finished, centrifugally washing the silver-plated copper powder, and drying in vacuum. According to the method, ethanol mixed liquid is used for heating ultrasonic treatment of copper powder, and active site density is improved. A double-complexing slow-release system is used for controlling the reaction rate, a complexing main agent is used for preventing particle aggregation caused by rapid reduction, and a complexing auxiliary agent is used for cooperatively regulating and controlling the Ag < + > release rate, so that a silver layer uniformly grows. And dropwise adding a silver-ammonia solution in a low-temperature gradient manner to realize gradual reduction of Ag < + >. The silver content of the prepared silver-plated copper powder is 20-25%, and the silver layer coverage rate is larger than or equal to 96%.

The application belongs to the technical field of Raman spectrum, and discloses a periodic Au / Ag cascade nanoflower array structure and a preparation method thereof. The preparation method comprises the following steps: S1, preparing a PS ball template, and performing reactive ion etching on the PS ball template; S2, preparing a silver-ammonia solution, adding the silver-ammonia solution and the PS ball template prepared in the step S1 into a beaker, adding a glucose solution, reacting at room temperature, removing the reaction solution after the reaction is completed, washing and drying the product with deionized water, and obtaining a silver nanoparticle-wrapped flower-shaped PS ball array; and S3, taking the silver nanoparticle-wrapped flower-shaped PS ball array as a sacrifice template, soaking the silver nanoparticle-wrapped flower-shaped PS ball array in an Au + solution to react, and obtaining the periodic Au / Ag cascade nanoflower array structure. The method realizes low-cost large-area preparation, and the obtained nanoflower array structure has a strong SERS enhancement effect.

The present application relates to silver nanowire preparation technical field, especially in kind of based on seed control's silver nanowine's preparation method.The present application mixes silver salt solution 1 and ammonia water, carries out complexation reaction, obtains silver ammonia solution;Polyvinyl pyrrolidone solution 1 and silver ammonia solution are mixed after adding formic acid solution, carries out redox reaction, obtains seed solution;Polyvinyl pyrrolidone solution 2, seed solution and sodium chloride solution are mixed after preheating to reaction temperature, and silver salt solution 2 is added, reaction is carried out, and silver nanowine is obtained.The present application utilizes fast nucleation + slow growth mode to prepare silver nanowine, in the preparation seed solution process, formic acid shows moderate reduction rate, can realize continuous uniform nucleation, thereby obtains small, narrow distribution silver seed, shortens the preparation time of seed, controls seed size and quantity.Seed solution is added to improved polyhydric alcohol solution, reduces silver nanoparticle byproduct, improves silver nanowine purity and uniformity.