136results about "Elemental selenium/tellurium" patented technology

The invention provides an iron-selenium double-monatomic nitrogen-doped carbon-based composite material and a preparation method and application thereof, the composite material comprises an N-doped carbon matrix, and Fe monatomic and Se monatomic distributed on the N-doped carbon matrix, and the Fe monatomic and the Se monatomic are anchored on the N-doped carbon matrix. The method comprises the following steps: preparing a Fe / Se / N-doped carbon-based precursor, and carrying out high-temperature carbonization on the Fe / Se / N-doped carbon-based precursor to obtain the iron-selenium double-monatomic nitrogen-doped carbon-based composite material. The preparation method overcomes the technical bottlenecks of low specific capacity, poor cycling stability, poor rate capability, complex preparation process, no environmental protection and the like of the existing sodium-ion battery negative electrode material. The composite material has high reversible capacity, excellent cycle stability and good rate capability, comprehensively improves the comprehensive electrochemical performance of the sodium-ion battery, provides a competitive high-performance material solution for the field of sodium-ion batteries, and practically meets the urgent demand of the current new energy field on high-performance battery materials.

The invention relates to a method for recovering tellurium from copper anode slime through cooperation of ultrasound and hydrogen peroxide, and belongs to the field of wet metallurgy of scattered metal. The method comprises the following steps: drying and grinding copper anode slime to obtain copper anode slime powder; the method comprises the following steps: adding copper anode slime powder into a sulfuric acid solution, mixing to obtain copper anode slime slurry, adding hydrogen peroxide into the copper anode slime slurry, carrying out ultrasonic enhanced leaching for 20-160min, and carrying out solid-liquid separation to obtain a leaching solution containing copper and tellurium and high-grade valuable metal leaching residues. According to the method, hydrogen peroxide is effectively promoted to be decomposed by ultrasound to generate hydroxyl radicals, the oxidation potential of a system is regulated and controlled, copper and tellurium are selectively converted into copper ions, tellurate radicals enter a solution, and valuable elements such as gold, silver and selenium are enriched in slag; necessary heat is provided for the reaction by utilizing the heat effect of ultrasonic and heat released by chemical reaction, and extra heating is not needed; strong jet flow generated by ultrasound effectively destroys raw material inclusion and secondary wrapping, reaction mass transfer is enhanced, and the leaching rate of tellurium is increased. The method disclosed by the invention is simple in leaching process operation, low in cost and high in reaction speed.

The invention discloses a method for separating and recovering selenium and mercury from acid mud containing selenium and mercury. The method comprises the following steps: mixing the acid mud containing selenium and mercury with water, performing wet ball milling, filtering and drying to obtain a ball milling material; adding a hydrogen peroxide solution into the ball-milled material, adding hydrochloric acid to adjust the acidity, carrying out oxidation acid leaching, and carrying out solid-liquid separation to obtain selenium-containing mercury liquid and selenium-removed mercury slag; adding thiourea into the selenium-containing mercury liquid for selective reduction, and performing solid-liquid separation to obtain crude selenium and reduction liquid; zinc powder is added into the reduction liquid for mercury replacement and precipitation, and crude mercury and precipitation liquid are obtained after solid-liquid separation; wherein the selenium-removed mercury slag and the precipitation solution are subjected to centralized treatment. The method is simple in process, convenient to operate and easy to process, selenium and mercury in the acid mud containing selenium and mercury can be removed at a time, efficient separation and recovery of selenium and mercury in the acid mud containing selenium and mercury are achieved, harmless treatment of hazardous waste and effective utilization of resources are achieved, and the method conforms to the concept of green sustainable development.

The invention discloses a method for recovering selenium and mercury from acid-making acid mud, and relates to the field of non-ferrous metal metallurgy. The method comprises the following steps: slurrying acid mud produced in a purification process in a sulfuric acid production process and concentrated sulfuric acid, roasting at low temperature to realize preliminary separation of mercury and selenium, distilling roasting residues to realize recovery of mercury in the acid mud, and returning distillation residues to a lead system to recover lead in the acid mud. The method can realize efficient separation of mercury and selenium in acid-making acid mud, has the characteristics of echelon recovery of selenium, mercury and lead, environmental friendliness and the like, is simple to operate, and has good economic benefits.

The invention relates to a method for preparing small-particle-size red nano-selenium particles and application of the small-particle-size red nano-selenium particles, and belongs to the technical field of selenium compounds. The nano-selenium particles contain nano-selenium and a lipoic acid oligomer. The preparation method comprises the following steps: respectively preparing nano-selenium and a lipoic acid oligomer, and uniformly mixing the nano-selenium and the lipoic acid oligomer to obtain the nano-selenium particles. The nano-selenium particles have good stability; the content of total protein and fat in highland barley grains to which the nano-selenium particles are applied is remarkably increased through detection, the nano-selenium particles become an effective means for selenium enrichment of crops, the nano-selenium particles are well applied to selenium-enriched planting of highland barley, and the application of the nano-selenium particles to the highland barley grains is developed by combining development of new selenium-enriched crop varieties and research of a new selenium fertilizer application technology. And a powerful promotion effect is achieved on the development of selenium-enriched ecological agriculture.

The invention discloses a method for recovering valuable metals from copper anode slime step by step, and belongs to the technical field of metallurgy and chemical industry. According to the method, through control over the oxidation-reduction potential, the oxidation-reduction potential is high in the leaching stage, and it is guaranteed that gold, selenium, tellurium and the like can be oxidized to enter a leaching solution; in the reduction stage, gold, selenium and tellurium products are reduced step by step according to the difference of gold, selenium and tellurium in reduction potentials; in the leaching stage, soluble chlorine salt is added while enough oxidation potential is guaranteed, enough chloride ions are provided for the solution, and therefore gold can enter the solution in the form of AuCl4-(tetrachloroauric acid); meanwhile, in the oxidation leaching stage, a small amount of silver enters the solution in the form of silver sulfate or silver complex, and under the condition that enough chloride ions are provided, silver is precipitated and retained in residues in the form of silver chloride, so that separation of gold and silver is achieved, and meanwhile dispersion of gold and silver in the leaching process is reduced. According to the method, valuable metal is efficiently separated and recycled.

A hydrometallurgical process for recovering a plurality of metals from a complex rare and precious material, comprising the following steps: step 1: adding a complex rare and precious material to a hydrochloric acid solution, adding an oxidant for reaction, and then performing filtration to obtain a chlorination liquid and a chlorination residue; step 2: using two-stage counter-current gold loading to obtain a gold-loaded liquid and a post-loading liquid, reducing the gold-loaded liquid, performing clarification to obtain an organic phase, and filtering a precipitate to separate a post-reduction liquid and sponge gold; performing evaporation and concentration on the post-reduction liquid to produce a concentrate 1 and a condensate; and cooling and crystallizing the concentrate, performing filtration to obtain residual oxalic acid, and returning the residual oxalic acid to the reduction process and a post-crystallization liquid to gold loading; step 3: performing low-temperature distillation on the post-loading liquid to obtain a concentrate 2; step 4: performing high-temperature distillation on the concentrate 2 to obtain a concentrate 3; step 5: performing directional crystallization and centrifugal filtration on the concentrate 3 to obtain a crystallization residue and selenous acid; and step 6: washing the crystallization residue by using cold water or a low-acid-level condensate produced in step 3, and performing filtration to obtain a tellurium residue and a palladium-platinum-rhodium-rich liquid.

The invention discloses a tellurium copper slag comprehensive treatment technology and a multi-element collaborative recovery method, and relates to the technical field of non-ferrous metal metallurgy and solid waste recycling, and the tellurium copper slag comprehensive treatment technology comprises the following steps: pretreatment and arsenic volatilization removal, selective acid leaching copper extraction, tellurium enrichment through alkaline oxidation, tellurium reduction and arsenic recycling. According to the method, by combining the advantages of a wet process and a pyrogenic process, the defects that in the prior art, arsenic cannot be effectively recycled in the tellurium-copper slag treatment process and the process is complex are overcome, efficient copper and tellurium separation is achieved through coordinated regulation and control of an acid / alkali medium and an oxidizing agent, arsenic is recycled in an industrial raw material form, and the limitation that only tellurium and copper are concerned in a traditional process is broken through.

The present application relates to the technical field of anode slime treatment, and discloses a method for removing antimony and tellurium from anode slime by multi-stage pressurization and chlorine-free process, which comprises the following steps: S1, anode slime pretreatment, S2, multi-stage pressurization treatment, S3, separation of antimony and tellurium from the anode slime, S4, preparation of sodium antimonate, S5, tail gas treatment, S6, waste liquid treatment, S7, post-treatment. The method is characterized by the following: one-stage pressurized thiourea transformation is used for deep copper removal, and two-stage pressurized sulfuration is used for chlorine-free antimony and tellurium removal. The process flow does not involve chlorine-containing substances, and the pressurized leaching of alkaline medium does not produce substances with strong corrosivity, thereby reducing the damage to the equipment. In the process of removing antimony and tellurium, the harmful substances generated during the reaction can be treated by waste gas and waste liquid treatment, and the by-products, precipitates, incompletely removed heavy metal ions, trace pollutants and the like in the tail liquid can be removed or converted into harmless substances, so that the tail liquid meets the discharge standard and the environmental pollution caused by the tail liquid discharge is reduced.

The application provides a method for separating selenium tellurium from high-selenium tellurium dioxide through multistage conversion, and belongs to the technical field of non-ferrous metallurgy. The method comprises the following steps: a, material preparation; b, primary conversion leaching: selectively reducing selenium in a solution containing a reducing agent at pH 8-11 to obtain a selenium tellurium-containing residue and a primary leaching solution; c, secondary conversion leaching: selectively leaching tellurium in a strong alkaline solution containing a reducing agent to obtain elemental selenium and a secondary leaching solution; and d, neutralization treatment: combining the two leaching solutions and adding acid to obtain high-purity tellurium dioxide. The method is simple to operate, short in production cycle, and realizes efficient separation of selenium tellurium. The purity of the obtained elemental selenium is greater than or equal to 95%, the purity of the obtained tellurium dioxide meets the requirements of electrodeposition for producing 4N tellurium, and the method is suitable for large-scale production.

The application relates to an ultrasonic treatment method of high-impurity copper anode slime. The ultrasonic treatment method is realized through hierarchical ultrasonic strengthening and synergistic leaching. In the first-stage leaching, hydrogen peroxide-oxygen-rich air composite oxidants are combined with ultrasonic cavitation effects to realize efficient oxidation leaching of arsenic, antimony and bismuth; in the second-stage leaching, sulfuric acid-sodium sulfite mixed leaching agents are used to remove harmful impurities such as arsenic, antimony and bismuth under ultrasonic strengthening, and to efficiently enrich valuable metals such as gold, silver, selenium and tellurium, so that the treatment period is shortened, energy consumption and reagent consumption are reduced, resource comprehensive utilization is improved, and the method is suitable for efficient separation and resource recovery of high-impurity copper anode slime containing refractory impurities such as arsenic, antimony and bismuth and valuable metals such as gold, silver, selenium and tellurium.

The present application belongs to the field of metallurgy, and relates to a method for producing antimony white by directly oxidizing crude antimony, comprising the following steps: S1, mixing crude antimony with crude antimony alloy, and reacting under an oxygen-containing atmosphere, to obtain oxidized slag and a melt after the reaction is completed; S2, adjusting the temperature of the melt, and then introducing compressed air to react, to produce antimony trioxide-containing flue gas, and to obtain antimony oxide slag after the reaction is completed. The present application makes full use of impurities such as sodium sulfide, sodium hydroxide and sodium thiosulfate contained in crude antimony, and innovatively uses these components for arsenic removal reaction, which not only avoids the cumbersome steps of adding various auxiliary materials in the traditional process, but also enables the original sodium sulfide, sodium hydroxide and sodium thiosulfate in the crude antimony to fully play a synergistic role, showing excellent performance in arsenic removal effect, thus simplifying the process flow, significantly reducing the production cost, and realizing the dual improvement of economic benefit and process efficiency.

This invention relates to the field of electrocatalysis technology, specifically to a single-element selenium-nickel-iron alloy composite electrocatalyst, its preparation method, and its application. Using nickel chloride, ferrous sulfate, urea, ammonium fluoride, and selenium dioxide as precursors, a two-step hydrothermal method is employed. In the first step, a nickel-iron alloy is prepared in situ on a foamed iron substrate using nickel chloride, ferrous sulfate, urea, and ammonium fluoride precursors. In the second step, selenium dioxide is used as a selenium source to composite elemental selenium with the nickel-iron alloy, resulting in the in-situ growth of a single-element selenium-nickel-iron alloy block catalyst on a foamed iron substrate. The electrocatalyst of this invention exhibits excellent catalytic activity and stability in the electrocatalytic water desorption oxygen reaction, meeting the requirements for large-scale industrial applications.

The invention provides a preparation method of selenium nanoparticles based on polyvinylpyrrolidone modification, which comprises the following steps: S1, reduction reaction: under the protection of inert gas, carrying out reduction reaction on a selenium source and sodium borohydride in an aqueous solution at room temperature to generate a sodium hydrogen selenide intermediate; s2, stabilizing reaction: adding a polyvinylpyrrolidone aqueous solution into the reaction system obtained in the step S1, and continuing to carry out stabilizing reaction under the protection of inert gas, so that polyvinylpyrrolidone is modified on the surfaces of the generated selenium nanoparticles; s3, purification and collection: purifying the reaction liquid obtained in the step S2, removing small molecular impurities, and then freeze-drying to obtain selenium nanoparticle solid powder based on polyvinylpyrrolidone modification. The preparation method of the selenium nanoparticles based on polyvinylpyrrolidone modification, provided by the invention, has the advantages of safer raw materials, simpler process, purer product and the like.

The utility model relates to a superfine selenium powder preparation device which comprises a gasification furnace, a connecting pipeline I is communicated with the gasification furnace, the other end of the connecting pipeline I is communicated with a vapor deposition furnace, a smoke exhaust port is formed in the top of the vapor deposition furnace, a discharge port is formed in the bottom of the vapor deposition furnace, and the superfine selenium powder preparation device further comprises a side blowing guide pipe. And a side blowing guide pipe is arranged beside the connecting pipeline I on the vapor deposition furnace. The device is simple in structure, low in cost and easy and convenient to operate, selenium steam is sufficiently and uniformly quenched by nitrogen, selenium powder products with consistent crystal granularity are obtained, the granularity of the prepared selenium powder can be applied to the high-end fields of photoelectricity, chemical medicine and the like, and uncrystallized selenium steam and impurities can be effectively recycled.

To provide a method for recovering selenium from an acidic aqueous solution containing selenous acid and ruthenium by suitably suppressing the incorporation of ruthenium in the precipitation recovery of selenium.SOLUTION: A method for recovering selenium comprises adding dimethyl sulfoxide to an acidic aqueous solution containing selenous acid and ruthenium, heating the acidic aqueous solution to a liquid temperature of 65°C or higher, adding a reducing agent to precipitate selenium, stopping the reduction, and then recovering the precipitated selenium.SELECTED DRAWING: None

A positive electrode material is disclosed, represented by the formula LiaNixCoyMn1-x-yMbO2-cQc, where 0.2≤a≤1.2, x≥0.6, y>0, b>0, and c>0. M comprises a high-valence cation and Q comprises an anion. The doping of a high-valence cation and an anion in a nickel-rich ternary material stabilizes the bulk structure during lithium deintercalation, reduces side reactions, lattice oxygen release, and transition metal dissolution, and improves cycling stability, high-temperature storage, and rate capability. The outer surface of the positive electrode material may further include a selenium-containing coating layer that reacts with residual lithium compounds and binds released lattice oxygen to suppress electrolyte oxidation. A conductive coating layer may be formed on the selenium-containing layer to prevent direct contact with the electrolyte and inhibit side reactions.

The invention discloses a method for separating inorganic selenium from a selenoprotein primary product. The technical problem of separating inorganic selenium from the existing selenoprotein primary product is solved, the selenoprotein is purer, the organic selenium content (99.99%) is higher, the biological activity and effectiveness of selenium are improved, absorption and utilization of life bodies are facilitated, and the side effects of the selenium are reduced. Based on the characteristics that inorganic selenium is larger than organic selenium in density and higher in electric conductivity, the technical scheme of combining a precipitation method, an ultrafiltration method, a reverse osmosis method and a dialysis method is adopted, the inorganic selenium existing in selenoprotein is separated out, and a purer selenoprotein product is obtained. After selenium protein powder, selenium yeast powder, selenium mushroom powder, selenium algae powder and other organic selenium primary products are separated through the process steps, high-purity (95%-99.99%) selenium protein, inorganic selenium and purified water are obtained. Environmental protection requirements are considered preferentially, zero emission is achieved in the separation process, and the method is extremely environment-friendly. The selenium protein is pure, selenium supplementation is not limited any more, and selenium supplementation popularization becomes possible.

The invention relates to the field of nano material preparation and agricultural fertilizer, and discloses a nano-selenium sol, a nano-selenium foliar fertilizer and a preparation method thereof, the selenium solubility in the nano-selenium sol is not lower than 20000 ppm, the surfaces of selenium particles in the nano-selenium sol are coated with a stabilizer, and the stabilizer is a nano-selenium foliar fertilizer. The stabilizer is at least one of sodium alginate, sodium carboxymethyl cellulose and polyvinylpyrrolidone. The stability of the nano-selenium foliar fertilizer is remarkably improved, and the problems of storage and transportation are solved. The leaf surface absorption and utilization efficiency is greatly improved, and efficient selenium enrichment is realized.

The invention belongs to the field of functional food and biomedicine, and relates to a method for preparing polysaccharide modified selenium nanoparticles. A chitosan oligosaccharide-sodium alginate compound is used as a stabilizer, Na2SeO3 is used as a selenium source, Vc is used as a reducing agent, novel selenium nano-particles (COS-SA-SeNPs) are prepared through a chemical synthesis method, the stability of the particles is improved, and the optimal preparation method is determined by taking the particle size as an index. Investigating the physical and chemical stability; the interaction mode of the COS-SA-SeNPs is defined; the influence of the COS-SA-SeNPs on HepG2 cell growth is further researched, and an action mechanism of inducing HepG2 cell ferroptosis by the COS-SA-SeNPs is disclosed. According to the invention, the stability of SeNPs is improved by preparing COS-SA-SeNPs, the anti-hepatoma activity of the SeNPs is proved, and reference is provided for further development and utilization of the SeNPs in the fields of functional foods with anti-hepatoma effects, foods for special medicine, foods for special diets and the like.

The application belongs to the field of nanometer materials, and specifically discloses an ultrathin platinum-based hollow nanorod with a wall thickness less than 4 nm, a preparation method and application thereof. The preparation method comprises the following steps: adding tellurium and selenium precursors into a solution containing a reducing agent and continuously stirring by magnetic force, then performing solid-liquid separation to obtain tellurium-selenium nanorods; obtaining a structure of a platinum alloy coated tellurium-selenium template, then adding hydrogen peroxide solution into an aqueous solution containing an intermediate product and reacting for a preset time, performing solid-liquid separation to obtain a precipitate after the reaction is completed, and finally obtaining the ultrathin platinum alloy hollow nanorod. If no other noble metal precursor is added when the platinum precursor is added, the ultrathin platinum hollow nanorod can be obtained. The application mainly controls the reaction rate of the noble metal precursor and the tellurium-selenium template by using ethylene glycol and polyvinylpyrrolidone, and removes the unreacted tellurium-selenium template by using hydrogen peroxide etching, so that the prepared ultrathin platinum-based hollow nanorod has a wall thickness less than 4 nm.

The application relates to the technical field of non-ferrous metal smelting and recycling, and discloses a method for reducing and separating selenium in acid sludge wet leaching liquid, which comprises the following steps: acid sludge chlorination leaching and rough selenium residue and post-depletion liquid generated by a step of reducing rough selenium from the leaching liquid; treating the post-depletion liquid through a neutralization and mercury precipitation step; mixing the rough selenium residue and the post-depletion liquid to perform alkaline leaching, adding NaOH to adjust the mass concentration to 10-20%, adding 1.05-1.20 times of the required amount of hydrazine hydrate under normal temperature and pressure, and separating an Se 2‑ alkaline leaching liquid; adding 1.0-1.15 times of the required amount of hydrogen peroxide to the Se 2‑ alkaline leaching liquid to perform oxidation and precipitate selenium, and separating a powder selenium product. Through the application, the side reaction dissolution of lead impurities is effectively inhibited, efficient separation of selenium and lead and mercury is realized, reagent consumption is reduced by combining with mother liquor circulation, and finally a high-purity powder selenium product is prepared.

The invention belongs to the technical field of powder material preparation, and particularly relates to a method for preparing selenium powder by using a freezing airflow crushing method, and the method comprises the following steps: dissolving selenium oxide in water to form a solution, and adding a reducing agent to carry out a reduction reaction to obtain a mixed solution containing elemental selenium; the mixed solution containing the selenium simple substance is subjected to evaporation, crushing, freezing airflow crushing and grading treatment, and the selenium powder is obtained; the freezing airflow crushing temperature is-40 DEG C to 0 DEG C; the pressure of the freezing air flow crushing is 2 to 15 bar. The method provided by the invention can realize accurate regulation and control of the particle size of the selenium powder, and the prepared selenium powder is uniform in particle size, high in purity and suitable for large-scale production.

This invention discloses a short-process purification method for tellurium from crude tellurium. The process first involves washing the crude tellurium with water to achieve liquid-solid separation, yielding washed crude tellurium. The washed crude tellurium is then subjected to pyrometallurgical oxidation to obtain tellurium oxide slag. This tellurium oxide slag is then leached to obtain a tellurium leachate. The tellurium leachate is subsequently subjected to electrowinning and casting processes to complete the tellurium purification. The advantages of this invention are: a short process flow, high yield, low chemical usage, and low cost. By combining pyrometallurgical and hydrometallurgical methods, crude tellurium is converted into 4N refined tellurium, effectively shortening the refined tellurium smelting process, reducing intermediate products, and increasing the tellurium yield to over 95%.

The invention belongs to the technical field of comprehensive recovery of scattered metal tellurium, and particularly relates to a method for recovering copper and tellurium from copper telluride slag. According to the method, metal copper and metal tellurium are effectively recovered through directional oxidizing roasting, water leaching copper and tellurium separation, alkaline leaching impurity removal and tellurium enrichment and neutralization and precipitation of tellurium dioxide, and meanwhile enrichment of precious metal with the extremely low content in the raw materials is completed; according to the method, the metal copper and the metal tellurium can be efficiently recovered from the copper telluride slag, the production process is simple, the recovery rate of the copper reaches 99% or above, the recovery rate of the tellurium can reach 90% or above, and the purity of tellurium dioxide is larger than 98%.

The application belongs to the technical field of new energy materials, and particularly relates to a tellurium / carbon diselenide composite material and a preparation method and application thereof. The tellurium / carbon diselenide composite material comprises reduced graphene oxide and tellurium / carbon diselenide nanorods embedded in the reduced graphene oxide; the tellurium / carbon diselenide nanorod is in a core-shell structure, the shell of the core-shell structure is carbon diselenide, and the core of the core-shell structure is tellurium. The tellurium / carbon diselenide nanorod is embedded in the reduced graphene oxide, so that the tellurium / carbon diselenide nanorod is not prone to aggregation and is uniformly dispersed. The one-dimensional structure of the tellurium / carbon diselenide nanorod can shorten the path of electron transmission, has an efficient channel for electron transmission, has a larger specific surface area, can obtain more active sites, and improves the catalytic and adsorption performance. Meanwhile, the core-shell structure combines selenium and tellurium materials and has high flexibility. In addition, the preparation process is simple, does not need high temperature and high pressure, has low cost, and is conducive to large-scale production and application.

The application discloses a kind of biocompatibility elemental selenium nanotubes and preparation method thereof, belong to the field of nano elemental selenium synthesis, homogeneous mixture is obtained by mixing cerium sulfate solution, sodium hydroxide solution and selenium hydrazine dispersion liquid, the concentration of cerium sulfate solution is 2~4mmol / L, the concentration of selenium powder in selenium hydrazine dispersion liquid is 300~380mmol / L, to obtain mixed system, the mixed system is carried out hydrothermal reaction at 60~90 DEG C, to obtain reaction liquid, the product in reaction liquid is separated and dried, and the cell experiment result proves that biocompatibility elemental selenium nanotube is obtained.The application solves the lack of controllable and stable synthesis problem existing in the synthesis process of the prior art elemental selenium nanotube, and facilitates the application in the medical field as a drug carrier in the later period.

The invention discloses a method for extracting tellurium from a sodium tellurite solution through electrodeposition, and belongs to the technical field of non-ferrous metal hydrometallurgy. The method comprises the following steps: dissolving crude tellurium dioxide in a sodium hydroxide solution at 60-90 DEG C to prepare a sodium tellurite electrolyte containing 200-240 g / L of tellurium and 90-110 g / L of sodium hydroxide; in the electrodeposition process, a composite additive composed of sodium ascorbate, pentasodium diethylenetriamine pentaacetate, sodium citrate and polyvinylpyrrolidone is synchronously added into the electrolyte. And carrying out electrodeposition for 14-15 days under the conditions that the current density is 40-60A / m, the voltage is 15-30V and the temperature is 15-30 DEG C. Through the synergistic effect of the composite additive, tellurite radicals in the anode region are remarkably inhibited from being oxidized into insoluble sodium tellurate, heavy metal impurity ions in the electrolyte are strongly complexed, and therefore the direct recovery rate of tellurium is increased to 90% or above while the better current efficiency is kept, and the purity of the obtained tellurium ingot reaches 99.95% or above.

The invention discloses a method for efficiently reducing elemental selenium from selenium-containing leachate based on ferrous sulfate, which comprises the following steps: taking the selenium-containing leachate obtained by oxidation and acid leaching, and adjusting the acidity of the leachate to 0.5-1.1 mol / L; ferrous sulfate is added into the acid-adjusted selenium-containing leachate according to the liquid-solid ratio of 2 mL: (1.0-1.4) g for a reduction reaction, the reduction reaction temperature ranges from 70 DEG C to 90 DEG C, the reduction reaction time ranges from 40 min to 80 min, and a reaction product I is obtained; and separating the precipitate of the reaction product I, washing and drying to obtain the elemental selenium. According to the method disclosed by the invention, the elemental selenium is extracted by reducing the selenium-containing leachate by adopting ferrous sulfate, and the reduction rate of selenium can reach 91% or above under limited conditions; under optimized conditions, the selenium reduction rate can reach 95.87%, which is significantly superior to that of existing processes such as a microbiological method.

The application discloses a process for recovering multiple metals from complex rare and precious materials by a full-wet method, which comprises the following steps: step 1: adding the complex rare and precious materials into a hydrochloric acid solution, adding an oxidizing agent to react, and then filtering to obtain a chlorination liquid and a chlorination residue; step 2: adopting two-stage countercurrent gold loading to obtain a gold-loaded liquid and a post-loading liquid, reducing the gold-loaded liquid, clarifying an organic phase, and filtering a precipitate to separate a post-reduction liquid and sponge gold; the post-reduction liquid is evaporated and concentrated to produce concentrated liquid 1 and a condensate; the concentrated liquid is cooled and crystallized, and the residual oxalic acid is filtered out to return to the original process, and the post-crystallization liquid is returned to gold loading; step 3: low-temperature distillation of the post-loading liquid to obtain concentrated liquid 2; step 4: high-temperature distillation of the concentrated liquid 2 to obtain concentrated liquid 3; step 5: directional crystallization and centrifugal filtration of the concentrated liquid 3 to obtain crystallization residue and selenous acid; and step 6: washing and filtering of the crystallization residue by using cold water or the low-acid condensate produced in step 3 to obtain tellurium residue and a palladium-platinum-rhodium-rich liquid. The process provided by the application has the advantages of no waste water generation, a short process flow and high recovery rate of precious metals.