4943 results about "Reducing agent" patented technology

The invention discloses crack-chloride ion double-triggered subsea tunnel corrosion-resistant concrete and a preparation method thereof, and relates to the field of subsea tunnel engineering materials. The concrete is prepared from the following components in parts by weight: 400 to 500 parts of Portland cement, 50 to 80 parts of fly ash, 60 to 100 parts of superfine mineral powder, 1000 to 1100 parts of coarse aggregate, 700 to 800 parts of fine aggregate, 140 to 160 parts of water, 10 to 20 parts of self-repairing microcapsules and 1 to 5 parts of a water reducing agent, the self-repairing microcapsule comprises a capsule wall material, a self-repairing material and a layered dihydroxyl composite metal oxide. A crack-chloride ion double-response system is constructed, and the limitation of traditional single trigger repair is broken through. When a crack with a certain width appears in the concrete, the capsule wall of the self-repairing microcapsule is broken to release the repairing component, so that effective filling of the crack is realized; and meanwhile, the layered double-metal hydroxide can directionally adsorb chloride ions to form a stable compound, so that the migration rate of the chloride ions is remarkably reduced.

The invention provides an early-strength rapid-repair grouting material and a preparation method thereof, and the early-strength rapid-repair grouting material is mainly prepared from the following raw materials: 50 to 150 parts of sulphoaluminate cement, 10 to 150 parts of aluminate cement, 200 to 350 parts of a regenerated gelling powder material, 1200 to 1400 parts of quartz sand, 50 to 100 parts of silica fume, 10 to 150 parts of mineral powder, 10 to 100 parts of fly ash, 15 to 50 parts of a composite retarder, 0.1 to 2 parts of a water reducing agent and 1 to 10 parts of an early strength agent. 0.01 to 1 part of a water-retaining agent and 200 to 300 parts of water. The early-strength quick-repair grouting material is characterized in that activated low-cementitious active mineral solid waste is adopted as a main cementitious material, and the product has excellent construction stability, low-carbon weather resistance, corrosion resistance, micro-expansion quick-hardening early strength and economical efficiency.

The invention discloses a direct-current hollow electrode hydrogen plasma furnace mineral powder smelting system and method and application, and belongs to the technical field of hydrogen metallurgy. The system comprises a hollow electrode gas powder injection hydrogen plasma gun system, a direct current bottom electrode ore-smelting electric furnace system, a fine ore and hydrogen supply system and the like. The hollow electrode and the furnace bottom electrode form a direct-current arc, hydrogen carrying mineral powder is sprayed into an arc area to generate high-temperature hydrogen plasma, mineral powder reduction is achieved, and metal and slag are separated. According to the method, hydrogen serves as a reducing agent, carbon emission is reduced, the reaction efficiency is high, energy consumption is low, and the method can be used for steelmaking, smelting of micro-carbon ferromanganese and titanium slag and recovery of valuable metal in nonferrous smelting waste slag and has good green metallurgy application prospects.

The invention discloses a high belite sulphoaluminate cement-based two-component grouting material and a preparation method thereof. The grouting material comprises a gelling component and a coagulating reinforcing component, wherein the gelling component is prepared from a high belite sulphoaluminate cement clinker and an additive A; the admixture A comprises a water reducing agent, a retarder and slow-release minerals; the coagulating and reinforcing component comprises ordinary Portland cement clinker, calcium hydroxide, gypsum and an additive B; the admixture B comprises a water reducing agent and an early strength agent. According to the high belite sulphoaluminate cement-based grouting material, the formula composition of the high belite sulphoaluminate cement-based grouting material is optimized, so that the hydration process of the high belite sulphoaluminate cement is more continuous and lasting, and the compressive strength of the obtained high belite sulphoaluminate cement-based grouting material can be continuously improved.

The invention belongs to the technical field of steel smelting, and particularly discloses a comprehensive utilization method of vanadium titano-magnetite, which comprises the following steps: S1, preparing the vanadium titano-magnetite into pellets, and carrying out reduction reaction to obtain direct reduced iron; s2, a carbonaceous reducing agent and the direct reduced iron obtained in the step S1 are mixed and smelted in a melt separation electric furnace, and slag and molten iron are obtained; a slag former is not added in the smelting process, the purity of the titanium slag is improved through optimal design of the furnace profile of the melting electric furnace and combination of various smelting process control means, the problems that refractory materials of the melting electric furnace are excessively eroded, the service life is short, slag-metal separation is difficult, smelting is difficult to control and the like are solved, and the purposes of high-grade titanium slag and long service life of the melting electric furnace are achieved.

The invention relates to the technical field of preparation of lithium sulfide, in particular to a method for preparing lithium sulfide through hydrogen reduction of lithium sulfate. According to the specific technical scheme, the method for preparing the lithium sulfide by reducing the lithium sulfate through the hydrogen comprises the steps that the lithium sulfate is smashed to be micron-sized and then fed into a fluidized bed reactor, then high-purity hydrogen preheated to 850 DEG C is introduced into the fluidized bed reactor from the bottom of the fluidized bed reactor, the reaction temperature is controlled to be 850 + / -20 DEG C, and the reaction time is controlled to be 5-10 min. The hydrogen reduction method is relatively low in reaction temperature (700-900 DEG C), hydrogen is used as a clean reducing agent, a reaction byproduct is only water, and the problems of insufficient purity, high energy consumption, serious environmental pollution and the like in a traditional lithium sulfide preparation method can be avoided. The introduction of the fluidized bed technology can greatly enhance the gas-solid phase heat and mass transfer efficiency, realizes the continuity and automation of the process, and is an important path for realizing the industrialization of the reaction.

The invention relates to the technical field of concrete, and particularly discloses super-retarded concrete for an ultra-large pile and a preparation method of the super-retarded concrete. The super-retarding concrete for the ultra-large pile is prepared from the following raw materials in parts by mass: 320 to 400 parts of a cementing material, 1820 to 1960 parts of aggregate, 20 to 28 parts of an inorganic-organic hybrid retarding reinforcing agent, 7.2 to 11.6 parts of a polycarboxylate superplasticizer and 85 to 98 parts of water, the inorganic-organic hybrid delayed coagulation enhancer is prepared by carrying out in-situ free radical polymerization reaction on a hydroxyl acrylate monomer, acrylamide and nano silicon dioxide. According to the inorganic-organic hybrid retarding reinforcing agent, a hybrid substance is formed through a chemical bond, an organic phase is chelated with calcium ions to realize retarding and does not excessively inhibit cement particles, inorganic phase nano silicon dioxide has no agglomeration risk, gaps are filled, a stable product is generated to resist alkali erosion, and the super retarding performance and the long-term strength of concrete are both considered; and the service life of the ultra-large pile is prolonged.

The invention relates to the field of organic chemical synthesis, in particular to a synthetic method and application of pyrimidone compounds. The invention provides a synthesis method, reactants are o-amino heterocyclic formamide and triethyl orthoformate respectively, a solvent system is a hexafluoroisopropanol solvent, and a product is a heterocyclic pyrimidone compound. The reaction does not need strong acid or strong alkali conditions, does not need additional reducing agents or oxidizing agents, does not need transition metal catalysis, is economical and practical, the reaction conditions are relatively mild, and the synthesized pyrimidone compound has a good antibacterial effect.

The invention discloses a preparation process of a waste concrete recycled aggregate gypsum-based wall material, which comprises the following steps: (1) mixing a water repellent agent with an anhydrous solvent to obtain a pretreating agent, and then adding concrete recycled aggregate for standing; and separating out the recycled aggregate and drying the recycled aggregate to obtain the pretreated recycled aggregate. (2) calcining the magnesium oxide whisker, and then adding the obtained calcined whisker into an ethanol solution of polyethylene glycol to form a suspension; and spraying the suspension on the continuously stirred pretreated recycled aggregate, and then carrying out heating and stirring treatment to obtain the modified recycled aggregate. And (3) uniformly stirring ardealite powder, silica fume, potassium hydroxide powder and fine aggregate, then adding water, a retarder and a water reducing agent, uniformly stirring, then adding the modified recycled aggregate, and uniformly stirring, thereby obtaining the product. The process provided by the invention not only reduces the adverse effect of the recycled aggregate on the gypsum-based material, but also improves the water resistance of the gypsum-based material and enhances the mechanical strength.

The invention discloses a liquid cement grinding aid and a preparation method thereof, and belongs to the technical field of cement grinding aid preparation, the liquid cement grinding aid comprises the following raw materials by weight: 76-80% of water, 18-20% of hydrochloric acid and 2-4% of sodium hexametaphosphate. The preparation method of the liquid cement grinding aid comprises the following steps: uniformly mixing the raw materials according to the weight percentage, and carrying out activation reaction to prepare the liquid cement grinding aid. The cement grinding aid disclosed by the invention is prepared by mixing hydrochloric acid, water and sodium hexametaphosphate according to a specific proportion, and through scientific regulation and control of the synergistic effect of all the components, the cement grinding aid has good grinding aiding performance and remarkably improves the specific surface area and grinding aiding efficiency of cement; the component design fully considers the cement hydration process and the compatibility with the water reducing agent.

The invention relates to the technical field of solid waste treatment and recycling, and discloses a waste incineration fly ash geopolymer composite material and a preparation method thereof, and the composite material is prepared from waste incineration fly ash, apatite minerals, zero-valent iron powder, persulfate and an alkali activator. The preparation method comprises the following steps: mixing the waste incineration fly ash, apatite minerals, zero-valent iron powder and persulfate to obtain composite powder; performing frequency conversion mechanochemical synergistic activation on the composite powder, wherein the activation process comprises a low-temperature activation stage and a high-energy pulse activation stage; and finally, mixing the activated powder with an alkali activator, pouring, molding and curing. According to the method, the reduction reaction and the oxidation reaction are driven step by step in the same system by regulating and controlling the mechanical energy input time sequence, the compatibility problem of a reducing agent and an oxidizing agent is solved, different types of persistent organic pollutants are synergistically degraded, meanwhile, heavy metal is stabilized, and the treatment effect is good. And the fly ash is recycled to prepare a geopolymer material with mechanical properties.

The invention relates to a waste ternary lithium ion battery black powder treatment method which comprises the following steps: in the presence of a reducing agent, carrying out acid leaching on waste ternary lithium ion battery black powder to be treated to obtain a leaching system; mixing the leaching system with iron powder, and reacting to obtain copper-removed ore pulp; and waste ternary lithium ion battery black powder is added into the copper removal ore pulp, the pH value of a reaction system is made to be 4-6, solid-liquid separation is carried out after reaction, and liquid with iron and aluminum removed and black powder filter residues are obtained. According to the treatment method, the technological process is short, production equipment can be simplified, the treatment cost is reduced, meanwhile, the recovery efficiency of valuable metal such as nickel, cobalt, manganese and lithium is effectively improved, the recycling value of black powder treatment is improved, and remarkable technical and economic advantages are achieved.

The invention relates to the technical field of concrete materials, and discloses rapidly-reinforced high-performance sprayed concrete for an existing tunnel lining and a preparation method of the rapidly-reinforced high-performance sprayed concrete. The sprayed concrete is prepared from the following raw materials in parts by weight: 300 to 350 parts of low-calcium high belite sulphoaluminate cement, 80 to 100 parts of superfine slag powder, 3 to 8 parts of a trigger type activating agent, 5 to 15 parts of slow-release particles, 2 to 5 parts of nanogel, 800 to 900 parts of fine aggregate, 800 to 900 parts of coarse aggregate, 30 to 50 parts of copper-plated steel fiber, 0.8 to 1.2 parts of polypropylene fiber, 30 to 40 parts of a viscosity-adjusting accelerator, 10 to 20 parts of a water reducing agent and 160 to 180 parts of water. The sprayed concrete is high in compressive strength and good in durability, the double threats of chemical corrosion and chloride ion permeation / steel bar corrosion are cooperatively solved, and the requirement for rapid reinforcement of tunnels and underground engineering is met.

The invention belongs to the technical field of concrete, and particularly relates to dynamic carbon injection recycled coarse aggregate concrete as well as a preparation method and application thereof. The preparation method of the concrete comprises the following steps: (1) adding the cement, the mineral powder, the recycled coarse aggregate, the fine aggregate, the fly ash, the carbon sequestration agent, the retarder and the water reducing agent into water, and uniformly stirring to obtain a mixed material; (2) injecting carbon dioxide into the mixed material to obtain carbon-mixed concrete; and (3) curing the carbon-mixed concrete to obtain the carbon-mixed concrete. The invention provides a method for preparing dynamic carbon injection recycled coarse aggregate concrete by taking a carbon sequestration agent, a retarder, cement, mineral powder, recycled coarse aggregate, fine aggregate, fly ash and a water reducing agent as raw materials. The method is simple in process and easy for large-scale production. The concrete prepared by adopting the method is relatively high in carbon sequestration rate, excellent in mechanical property and capable of effectively avoiding rapid hydration.

The invention relates to the technical field of building materials, and provides washing gangue concrete with high slump loss resistance and a mixing process thereof. The high-slump-retaining washed gangue concrete is prepared from the following raw materials in parts by weight: 200 to 220 parts of cement, 140 to 150 parts of mineral powder, 60 to 65 parts of fly ash, 680 to 720 parts of machine-made sand, 950 to 970 parts of washed gangue, 150 to 160 parts of water, 16 to 17.5 parts of a water reducing agent, 0.15 to 0.3 part of a slump retaining agent and 4 to 4.3 parts of polyethylene glycol. The slump retaining agent is hydroxypropyl methyl cellulose ether; and the viscosity of the hydroxypropyl methyl cellulose ether is 100 thousand mPa.s to 300 thousand mPa.s. According to the technical scheme, the problems of poor slump retaining performance and low compressive strength of washed gangue concrete in the prior art are solved.

The invention relates to the field of concrete, and particularly discloses anti-crack concrete and a preparation method thereof. The anti-crack concrete is prepared from the following raw material components in parts by weight: 400 parts of cement; 1000 to 1100 parts of coarse aggregate; 730 to 800 parts of fine aggregate; 40 to 50 parts of modified rubber particles; 20 to 25 parts of basalt fiber; 5-6 parts of a water reducing agent; 1.3 to 1.5 parts of SAP resin; 0.015 to 0.02 part of an air entraining agent; 130 to 140 parts of water; a modifier used for preparing the modified rubber particles is sodium hydroxide and a silane coupling agent. The anti-crack concrete disclosed by the invention has good anti-crack capability, the total cracking area does not exceed 35mm < 2 > / m < 2 >, and the 28d compressive strength is not lower than 40MPa.

The invention provides a preparation method of a multi-source coal-based solid waste filling material, and belongs to the technical field of solid waste reutilization, and the preparation method comprises the following steps: uniformly mixing cement, fly ash, furnace bottom slag, desulfurized gypsum, coal gangue, gasified slag and a water reducing agent to obtain a mixed material; and adding fluorine-containing mine water into the mixed material, stirring and mixing to obtain the cemented multi-source coal-based solid waste filling material with predetermined fluidity and bleeding rate. The invention further provides application of the multi-source coal-based solid waste filling material. According to the preparation method and application of the multi-source coal-based solid waste filling material, the coal-based solid waste can be comprehensively recycled and is environmentally friendly, and the prepared multi-source coal-based solid waste filling material can effectively control and treat fluorine ions in mine water.

The invention relates to a polycarboxylate superplasticizer compounding production line. The production line comprises an intelligent raw material pretreatment unit, a multi-component precise proportioning unit, a gradient temperature control compounding reaction unit, an online quality monitoring feedback unit and a finished product self-adaptive filling unit which are connected in sequence. The multi-component precise proportioning unit is internally provided with a dynamic proportioning adjusting system, and the feeding amount can be corrected according to the solid content deviation of raw materials and the target fluidity; the gradient temperature control compound reaction unit realizes temperature and speed coordinated regulation and control through a sectional temperature control module and a stirring speed linkage device; and the online quality monitoring feedback unit forms closed-loop control with the above two units by means of a near infrared spectrum detection module. The invention aims to solve the problem that the existing production line lacks the dynamic ratio adjustment of the actual solid content deviation of the raw material and the target fluidity, the reaction stage temperature control and stirring rate cooperative regulation and control and the online detection closed-loop control; therefore, the problems of low proportioning precision, poor reaction process controllability and large performance fluctuation of the water reducing agent are solved.

The invention belongs to the technical field of rare earth metallurgy and resource comprehensive utilization, and particularly relates to a method for separating and recycling iron and rare earth elements in rare earth iron ore. According to the method for separating and recycling the iron and the rare earth elements in the rare earth iron ore, the iron and the rare earth elements in the rare earth iron ore are recycled through MgO reduction roasting, and the efficient separation and extraction process of the iron and the rare earth elements is achieved by adding additives such as a reducing agent and MgO and through the procedures of reduction roasting, magnetic separation, selective leaching and selective precipitation. And comprehensive utilization of the rare earth-containing iron ore can be effectively realized.

The invention provides a method for recovering Si, C and TiO2 based on chlorinated waste salt water quenching slag, which comprises the following steps: sequentially carrying out water quenching dissolution, precipitation separation and filter pressing dehydration treatment on chlorinated waste salt to obtain water quenching slag and supernate; adding a dilute acid solution into the water-quenched slag, dissolving, and adding a reducing agent for reaction to obtain slurry; carrying out solid-liquid separation on the slurry to obtain a solid material and filtrate; the filtrate is pumped into a boiling bed separator, the petroleum coke and TiO2 are intercepted by a medium material layer, clear liquid is discharged, then the medium material layer is subjected to backwashing regeneration, and the desorbed petroleum coke and TiO2 are subjected to graded enrichment by a hydrocyclone, so that petroleum coke slurry and TiO2 slurry are obtained. According to the method, TiO2, C and other resources in the water-quenched slag obtained after molten salt chlorination waste salt water quenching are recycled, and the technical problem that in the existing chlorination waste salt resourceful treatment process, Si, C, TiO2 and other resources in the water-quenched slag are wasted is solved.

The invention discloses a preparation method of a lithium iron phosphate positive electrode material, three iron sources with different forms and different particle sizes participate in preparation of the lithium iron phosphate positive electrode material, and gradation is formed to improve the compaction density and rate capability of the material. The EDTMPA reduces the viscosity of the slurry, is anchored on the surface of FePO4 particles through strong adsorption, inhibits particle aggregation through steric hindrance and electrostatic repulsion effect, and introduces hydrophilic groups to enhance wettability, reduce the viscosity of the system, optimize dispersion stability, accelerate particle crushing and refining, reduce the particle size and shorten the grinding time; in the sintering process, a reducing agent is generated through pyrolysis to inhibit too fast oxalic acid decomposition to cooperate with the generated reducing gas, Fe < 3 + > is completely reduced, the reduction temperature is reduced to inhibit grain growth, and the grading effect between large and small particles is improved; in addition, an N-doped carbon coating layer is formed through high-temperature cracking, pores are filled with residual carbon generated through decomposition of ferrous oxalate, the coating density is improved, the carbon-coated graphitization degree is improved, and then the electronic conductivity and the rate capability of the material are improved.

The invention relates to the field of maintenance engineering materials, in particular to road and bridge interface high-bonding mortar and a preparation method thereof. The road and bridge interface high-bonding mortar is prepared from the following raw materials in parts by mass: 90 to 120 parts of gel material, 100 to 150 parts of aggregate, 30 to 45 parts of auxiliary emulsion, 10 to 18 parts of composite powder, 3.5 to 7 parts of reinforcing agent, 0.5 to 1 part of water reducing agent, 0.3 to 0.6 part of cellulose ether, 0.2 to 0.3 part of starch ether, 0.8 to 1.5 parts of thixotropic agent, 0.3 to 0.6 part of defoaming agent and 20 to 40 parts of water. The finally prepared road and bridge interface bonding mortar can maintain excellent durability, environmental weather resistance and anti-erosion effect while ensuring high-strength bonding performance, so that the mortar requirements of more existing complex construction environments are met.

The invention belongs to the technical field of building materials, and particularly relates to a micro-expansion anti-cracking waterproof composite deep groove filler and a preparation method thereof. The micro-bulking anti-cracking waterproof composite deep groove filler provided by the invention comprises cement, gypsum, mineral powder, nano silicon oxide, coarse aggregate, fine aggregate, modified fibers, an expanding agent, a polycarboxylate superplasticizer and water. According to the invention, polyacrylamide, calcium sulphoaluminate and magnesium oxide are adopted to jointly form an expanding agent, and early-stage-late-stage full-period shrinkage compensation is jointly formed in a concrete hydration process, so that the density of the concrete is effectively improved, and the waterproof performance of the concrete is further improved; according to the invention, sodium dodecyl benzene sulfonate and propylene glycol block polyether are adopted to carry out compound modification on graphene oxide, and gamma-aminopropyltriethoxysilane is connected to the surface of basalt fiber, so that the bonding strength of basalt fiber and a cement matrix and the compactness of the cement matrix are improved, and the waterproof and anti-cracking properties of concrete are further improved.

The invention belongs to the technical field of conductive polymer materials, and particularly relates to a three-dimensional polypyrrole conductive material and a preparation method and application thereof. The preparation method of the three-dimensional polypyrrole conductive material comprises the following steps: (1) preparing a metal copper quantum dot and graphene oxide mixed dispersion liquid; (2) adding an oxidizing agent to obtain a reaction solution; (3) adding a pyrrole monomer, and carrying out a polymerization reaction to obtain a graphene oxide / polypyrrole composite dispersion liquid; and (4) adding a reducing agent to reduce the graphene oxide to obtain the three-dimensional polypyrrole conductive material. After the metal copper quantum dots are loaded on the graphene oxide sheet layer, the graphene oxide sheet layer becomes a structure-oriented core in subsequent polymerization, and finally the stable three-dimensional conductive composite material with graphene as a framework and polypyrrole nanosheets as connection points is formed. Compared with a traditional three-dimensional material formed by overlapping and integrating a two-dimensional graphene sheet layer and a conductive nanowire / nanorod, the three-dimensional material with the structure can form an efficient conductive path more easily under the condition of low filler content.

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

The invention provides high chloride ion permeation resistance steel fiber fine aggregate concrete and a preparation method thereof. The high chloride ion permeation resistance steel fiber fine aggregate concrete comprises the following raw materials in parts by weight: 200-300 parts of cement; 30 to 50 parts of metakaolin; 100 to 200 parts of fly ash; 50 to 100 parts of mineral powder; 1-8 parts of nano silicon dioxide; 800 to 1000 parts of sand; 800 to 1000 parts of stone; 10 to 60 parts of steel fiber; 150 to 200 parts of water; and 5-20 parts of a water reducing agent. The steel fiber fine aggregate concrete with high chloride ion permeation resistance has the advantages of improved mechanical properties and durability, extremely high chloride ion permeation resistance, excellent volume stability, low material cost, economic feasibility of large-scale application, and wide application prospect. And the strict service requirements of the urban rail transit ballast bed under the long-term dynamic load, stray current and erosion medium coupling effect are precisely met.

The invention provides high-performance silver powder suitable for TOPCon battery fine grid silver paste, a preparation method of the high-performance silver powder and the silver paste, and belongs to the technical field of photovoltaic materials. The preparation method comprises the steps that a silver salt solution and a composite reducing agent are mixed, a first-stage hydrothermal reaction is carried out at the first temperature, a second-stage hydrothermal reaction is carried out at the second temperature, and silver powder is obtained after centrifugation, washing and drying; wherein the composite reducing agent is selected from a mixture of two of potassium tartrate, sodium sulfite and ferrous sulfate. According to the method, gradual growth and crystallinity improvement of silver crystal nucleuses are achieved through two-stage heating, particle aggregation or uneven morphology caused by rapid reduction is avoided, in addition, the adopted composite reducing agent combination is remarkably superior to a single reducing agent (such as ascorbic acid), and the morphology and particle size distribution of the silver powder can be more accurately regulated and controlled.

The invention relates to an indole hair dye based on air oxidation. The hair dye provided by the invention is characterized in that a chemical strong oxidant is not added, and oxygen in air can be catalyzed by using an air oxidation catalyst and a metal ion catalyst to naturally finish the oxidative polymerization process of indole substances (natural bionic melanin precursor substances). The used reducing agent is a combination of cysteine and a derivative thereof and sodium sulfite and a derivative thereof, the oxidative polymerization speed of indole substances can be controlled, and finally generated melanin macromolecules are embedded in hair cortex, so that white hair is obviously blackened. The natural oxidation process does not need hydrogen peroxide, destructive strong base or organic base, so that the use of harmful chemical reagents is reduced, the formula is simplified, the hair dyeing process is milder, potential hazards to hair and scalp are reduced, and the natural oxidation hair dye is safe, environmentally friendly and sustainable.

The invention relates to the technical field of photovoltaics, and discloses photovoltaic conductive silver-coated copper micro powder and a preparation method thereof, and the preparation method aims to solve the problem that performance and cost of existing silver-coated copper micro powder in photovoltaic application are difficult to consider at the same time. Through pH adjustment, organic pre-bonding treatment and gradient ammonification, the activity of the copper powder is reserved, and a uniform copper-ammonia complexing layer is constructed; in the chemical silver plating stage, the pretreatment liquid is added into a composite base solution containing a complexing agent, organic amine, a dispersing agent and a combined reducing agent, and a silver-ammonia solution is dropwise added for reaction under ultrasonic dispersion and nitrogen introduction protection; and in the post-treatment stage, a finished product is obtained through ethanol reflux desorption, antioxidant treatment, vacuum drying, low-temperature plasma activation and screening, uniform and complete coating of a silver layer can be achieved under the low silver content, and a feasible path is provided for replacing photovoltaic pure silver powder with silver-coated copper micro powder on a large scale.

Method for preparing a catalyst composition comprising indium bismuth alloy which method comprises (a) combining at least an indium containing salt, a bismuth containing salt and an oxalate salt in a liquid to obtain a precursor mixture; (b) combining the precursor mixture with a reducing agent to obtain a suspension comprising the catalyst composition; and (c) separating the catalyst composition from the suspension, wherein a support material is either added to the precursor mixture or to the reducing agent, and to catalyst composition comprising indium bismuth alloy obtainable by this method.