9 results about "Chromate salt" patented technology

The invention belongs to the technical field of building materials, and relates to disposable redispersible asphalt powder as well as a preparation method and application thereof. The asphalt powder comprises the following components in parts by weight: 100 parts of asphalt, 2-20 parts of an emulsifier, 5-20 parts of protective colloid, 0.5-40 parts of a stabilizer, 1-10 parts of a slow-release complexing agent and 5-20 parts of an anti-caking agent. The slow-release complexing agent is one or more of activated modified borax, modified boric acid, modified sodium silicate or chromate, and the activation mode of the slow-release complexing agent is that an inorganic salt aqueous solution and a part of the protective colloid solution are mixed in advance. The specific slow-release complexing agent is introduced and forms a synergistic system with the emulsifier, the protective colloid and the like, so that the asphalt powder can be quickly redispersed when meeting water for construction for the first time, the complexing agent and a hydrophilic component are subjected to irreversible reaction after drying and film forming, redispersibility is permanently lost, and the technical problem that a traditional product is poor in water resistance after film forming is effectively solved. The product is suitable for the fields of waterproof and anticorrosive dry-mixed mortar, asphalt coiled material base layer treating agents and the like.

The invention provides a steel wire quenching process, and relates to the technical field of heat treatment, and the steel wire quenching process comprises the following steps: S1, pretreatment: a steel wire to be quenched is sequentially subjected to alkali washing, acid pickling and passivation treatment, the alkali washing treatment is performed for 5-8 min by using a 8%-12% sodium hydroxide solution at 50-70 DEG C, the acid pickling treatment is performed for 3-5 min by using a 15%-20% hydrochloric acid solution at 20-30 DEG C, the passivation treatment is performed for 1-2 min by using a chromate solution at room temperature, and then the steel wire is aired; and S2, induction heating: the pretreated steel wire is heated to 880-920 DEG C by a medium-frequency induction heating device in a segmented mode, heat preservation is conducted for 5-8 s, and complete austenitizing is achieved. In the method, the temperature control precision is improved, the surface temperature difference of the steel wire is smaller than or equal to + / -5 DEG C through induction heating, the austenitizing uniformity is improved, the tensile strength fluctuation range of the quenched steel wire is reduced to be smaller than or equal to 5%, and the product percent of pass is high. The water-soluble quenching liquid is free of oil smoke emission, the cyclic utilization rate is larger than or equal to 90%, the COD value of waste liquid is smaller than or equal to 500 mg / L, compared with mineral oil quenching, pollutant emission is reduced by 92%, and the salt bath quenching salt slag generation amount is reduced to zero.

The invention provides a magnesium alloy coating agent and a preparation method thereof, a magnesium alloy surface treatment method and a magnesium alloy product, and the magnesium alloy coating agent comprises 30-80 g / L of ammonium fluotitanate ((NH4) 2TiF6), 10-30 g / L of sodium molybdate (Na2MoO4), 5-15 g / L of plant tannic acid, 3-10 g / L of L-ascorbic acid, 1-5 g / L of rare earth cerium nitrate (Ce (NO3) 3), 0.1-1 g / L of graphene quantum dots (the particle size is smaller than or equal to 10 nm), 5-20 g / L of sulfamic acid (H3NSO3) and the balance deionized water. Traditional harmful components such as phosphate and chromate are completely abandoned, international environmental protection standards such as ROHS and REACH are met, plant tannic acid (natural polyphenol) and L-ascorbic acid (vitamin C derivatives) replace traditional petroleum-based complexing agents, environmental toxicity is reduced, an acid system adjusted by sulfamic acid only needs to be neutralized and then flocculated and precipitated, and the treatment cost is reduced by 60% or above compared with phosphorus-containing wastewater; the magnesium alloy coating agent can also form a double-phase film layer structure, a neutral salt spray test is more than or equal to 72 hours (generally less than or equal to 24 hours), and the integrity of the film layer is far better than that of a traditional phosphating process.

The invention discloses a preparation method and a usage method of an anti-salt spray erosion agent for the shell of 18650 lithium batteries. The raw material ratio is as follows: refined vegetable oleic acid 5-10%, triethanolamine 5-8%, sodium molybdate 0.5-1%, fatty alcohol polyoxyethylene ether acidic phosphate 3-5%, sodium salt of sulfuric acid mono(2-ethylhexyl) ester 0.1-0.5%, n-propanol 4-8%, dodecenyl succinic acid 0.5-1.5%, and deionized water is added to make up 100%. The main active components of the anti-salt spray erosion agent of the invention can interact with the shell of 18650 lithium batteries. The active components penetrate through the voids on the surface of the shell, adsorb and combine with metal atoms, and then form a firm protective film. This protective film will not fall off after being rinsed with pure water, and can pass the 8-hour salt spray test. After the test, the defect area grade of the shell of 18650 lithium batteries is not lower than grade 4. This anti-salt spray erosion agent is an environment-friendly product and does not contain substances such as chromate, nitrite, and phosphate.

The present invention discloses a gun-black tin-nickel alloy electroplating and electrolytic protection process. The electroplating process comprises: 240-280 g / L potassium pyrophosphate, 50-60 g / L nickel chloride hexahydrate, 7-9 g / L stannous chloride dihydrate, 1-2 g / L lanthanum chloride or praseodymium chloride, 13-18 g / L potassium thiocyanate, 0.6-1.8 g / L methionine, 20-30 g / L ammonium citrate, 4-6 g / L disodium ethylenediaminetetraacetic acid, a pH range of 7.8-8.2, a plating bath temperature of 35-40°C, a cathode current density of 1-3 A / dm2, and a cathode travel of 3-5 m / min. The electrolytic protection process is as follows: 2-5 g / L cerium chloride, 2-5 g / L sodium molybdate, 15-30 g / L sodium hydroxyethylidene diphosphonate, 100-150 g / L anhydrous potassium carbonate, pH range 11-13, room temperature operation, cathode current density 0.5-1.2 A / dm², using the plated part as the cathode and the titanium plate as the anode, and electrolysis for 60-120 seconds. The prepared gunmetal black tin-nickel alloy plated part was subjected to a neutral salt spray test for 96 hours in accordance with GB / T 10125-2021 "Artificial Atmosphere Corrosion Test Salt Spray Test", and no corrosive products were generated on the surface of the coating. The gunmetal black tin-nickel alloy electroplating and electrolysis process of the present invention improves the corrosion resistance of the coating and solves the high pollution problem of the dichromate electrolytic protection method.

The present invention relates to the technical field of water electrolysis, and particularly to an electrolyte additive for improving water electrolysis reaction performance, an electrolyte, an electrolyte solution, and a method for improving water electrolysis reaction performance. The additive includes a non-metal oxyacid salt (sulfate, phosphate, borate, selenate, silicate, carbonate, perchlorate, trifluoroacetate, etc.) and an aqueous solution thereof, and an oxometallate (molybdate, tungstate, vanadate, chromate, niobate, ferricyanate, zincate, aluminate, stannate, etc.) and an aqueous solution thereof, as electrolyte solution additives for a water electrolysis reaction. The present invention provides a use of an oxyacid salt for improving the activity and stability of oxygen evolution during water electrolysis. In particular, the oxyacid salt is also suitable for electrolysis reactions carried out at high and low temperatures. Due to the addition of the oxyacid salt, the present invention reduces the oxygen evolution reaction potential and the charge transfer resistance, increases the electron transport rate, and exhibits relatively fast chemical reaction kinetics, thereby facilitating the improvement of the reaction activity.

A method for co-removing chromium and silicon from a sodium-containing vanadium solution by selective reduction. The method comprises: adjusting the pH value of a sodium-containing vanadium solution such that the pH value of the system solution is 10.5-11.5 at 60°C to obtain a pretreated sodium-containing vanadium solution; adding a preset amount of reducing agent to the pretreated sodium-containing vanadium solution at a time for reduction reaction; adding a silicon removal agent to a reaction system at the last stage of the reduction reaction for reaction to obtain a first intermediate reaction solution, carrying out solid-liquid separation on the first intermediate reaction solution, washing a solid phase with water, and then combining the solid phase with a filtrate to obtain an impurity removal solution; and carrying out an oxidation purification treatment on the impurity removal solution to obtain a purified solution. In the present invention, under specific concentration and pH conditions of a sodium-containing solution, vanadium mainly exists in the form of a pyrovanadate, shows relatively low oxidizability and stable properties, and is not prone to reducing. Even if a small part of vanadium is reduced, vanadium still remains as a vanadite in the solution, while a chromate is selectively reduced into chromium hydroxide, thereby completing the separation of vanadium and chromium in the form of a chromium hydroxide precipitate.

This invention discloses a corrosion-resistant and recyclable tinplate food container and its preparation method, comprising a food can with a threaded post at the center of its top. A sealing cap is connected to the top of the threaded post via an internally threaded tube. A connecting ring is provided on one side wall of the sealing cap. The advantages are as follows: Through the design of the weld seam, electroplating layer, and passivation layer, after welding the joint, the weld seam can be electroplated using a tin salt electrolyte, filling any damage to the tin layer. Then, a secondary passivation process using a chromate passivation solution is performed on the weld seam to form a passivation layer, effectively connecting the weld seam to the original passivation layer and preventing localized corrosion at the weld seam. The design of the connecting ring, connecting ring 2, and carrying rope facilitates direct hand-carrying of the food can when carrying the device, preventing the loss of the sealing cap and facilitating efficient recycling of the tinplate.

The application relates to the technical field of medical intermediates, in particular to a preparation method of 2-fluoro-3-nitrobenzoic acid, which comprises the following steps: S1: 2-fluoro-3-nitrotoluene is subjected to reflux reaction with DMF-DMA to obtain an intermediate (E)-2-(2-fluoro-3-nitrophenyl)-N,N-dimethylvinyl-1-amine; S2: the intermediate is dissolved in an aprotic solvent, is subjected to low-temperature ozone oxidation, is subjected to vacuum distillation to remove the solvent, and is subjected to acid system crystallization to obtain 2-fluoro-3-nitrobenzoic acid. The route realizes efficient conversion of methyl into carboxyl through an "activation-directional oxidation" strategy, and avoids the safety and environmental protection problems caused by strong oxidation systems such as potassium permanganate and bichromate. Ozone oxidation is high in selectivity and mild in reaction, can effectively inhibit the side reaction of the aromatic ring nitro and the fluorine substituent, and the product is high in purity.