30 results about "Dichromate salt" patented technology

The invention relates to a process for preparing chrome acid anhydride from ferrochrome through an acid soluble electrolytic method. Ferrochrome is ground into fine powder and placed into a reaction still, acid is added to dissolve the ferrochrome, special substances are added for reaction with heating, trivalent chromium and ferrous ions are separated, then a trivalent chromium solution is placed into an electrolytic cell, the trivalent chromium is completely converted into hexavalent chromium through electrolytic oxidation, and chrome acid anhydride products are prepared. Through the process, series chromium compounds including dichromate, chromium sulfate, chromic chloride, chromic oxide, chromic hydroxide, a chrome tanning agent, chromium picolinate and chromium nicotinate, iron series pigment including ferrous oxalate, iron blue and ferbam, new materials including silicon and carbon, and new energy, namely hydrogen, are prepared simultaneously. The process is advanced, short in technological process, capable of saving energy and environmentally friendly, the produced products are good in quality, high in value and good in benefit, and the sustainable development of the chrome salt industry can be better prompted.

The invention relates to a method for removing calcium and magnesium alkaline-earth metal ions contained in a chromate solution by adopting ion exchange resin, belonging to the technical field of refining of the chromate solution. A process course comprises the following steps of: adding a chemical refined preparation to remove a large majority of impurities; filtering suspended matters contained in the suspended matter by using a filter to obtain a chromate solution with suspended matter content less than 1 mg / L; dynamically contacting the obtained chromate solution with the ion exchange resin to carry out ion exchange; and diluting or concentrating the obtained chromate solution to prepare a feed solution suitable for electrolysis. The invention has the advantages that the chromate solution containing obviously reduced calcium and magnesium can be obtained and is very suitable for being used as the feed solution of chromate synthesized into dichromate till chromic anhydride through electrocatalysis; and the ion exchange resin saturated by adsorption can be repeatedly used by being washed, regenerated and transformed; and in addition, the method has the advantages of moderate process condition, easy operation, little pollution, low cost and easy resin regeneration, and can realize the continuous large-scale production.

The invention relates to a process for preparing chromic anhydride and dichromate by a carbon ferrochrome liquid phase method and belongs to the technical field of preparation of chromic compounds, ferrum-series pigments, silicone new materials, photovoltaic new materials and new-energy chemical-industry new materials from industrial metallurgical products. The process disclosed by the invention is advanced, energy-saving and environment-friendly and is free of emission of waste residues, waste gases and waste water. Products such as the chromic compounds, the pigments, new energy sources and new-energy-source silicon-carbon battery materials are produced from ferrochrome by a liquid phase method in one time without high pressure and high temperature, so that a series of novel high-end industry chains are formed, and the original situation that the ferrochrome is single in use and pure in production is thoroughly changed; the out-of-date production process that heavy pollution generated by the original chromate compound roasting production heavily harms environment is changed, and the production of chromic anhydride, dichromate and the chromic compounds can be in a energy-saving, environment-friendly and high-benefit development path; and the field of diversified development and application of ferrochrome industry is extremely extended, the international competitiveness of enterprises is greatly enhanced, and the optimized upgrading and developing of national industries are promoted, so that the process is of far reaching importance. The process meets the modern requirements on environment-friendly development of economy and has very good enterprise economic benefit, perfection benefit and social benefit.

The invention belongs to the field of water detection. The invention relates to a dichromate method for determining chemical oxygen demand in water. The dichromate method comprises the following steps: preparing a potassium dichromate standard solution, an ammonium ferrous sulfate standard solution, a mercury sulfate solution, a COD quality control standard solution and a ferrous sulfate indicator; preparing a calibration sample, a blank sample, a quality control sample and a to-be-detected sample; digesting the blank sample, the quality control sample and the to-be-detected sample, and addinga silver sulfate-sulfuric acid solution and ultrapure water; adding a ferrous sulfate indicator into the to-be-detected sample, the blank sample, the quality control sample and the calibration samplewhich are cooled to room temperature, and titrating by adopting an ammonium ferrous sulfate standard solution; recording the volume of the ammonium ferrous sulfate standard solution dropwise added into each sample; and calculating the actual concentration of the ammonium ferrous sulfate standard solution and the mass concentration of the chemical oxygen demand in the water according to a formula.The detection method is simple to operate, accurate in detection result and small in pollution.

The invention relates to the technical field of chemical production, in particular to a method for preparing 4,4'-diaminodiphenylmethane. The method for preparing 4,4'-diaminodiphenylmethane is characterized by comprising the steps of; adopting a mode of soaking activated carbon in a mixed solution of excessive dichromate salt or chromate salt with an inorganic strong acid to prepare acid-modifiedactivated carbon; putting the acid-modified activated carbon and aniline in a reaction kettle, adding a formaldehyde aqueous solution dropwise in a nitrogen atmosphere, performing full stirring at the same time, and performing an initial reaction after the addition; and performing vacuum rectification to purify the reaction product so as to obtain the product. The method for preparing 4,4'-diaminodiphenylmethane has a simple preparation process and mild synthesis reaction conditions, the adopted catalyst has low cost, high catalytic activity and stability, high product selectivity, can be separated from the product easily, and can be used repeatedly, and therefore the method for preparing 4,4'-diaminodiphenylmethane is suitable for wide promotion and application.

The invention discloses a combined inhibitor for the separation of copper-lead sulfide ore and its application. Its active components include ferric chloride and 2-phosphonic acid butane-1,2,4-tricarboxylic acid PBTCA, with a mass ratio of (0.5~6): (2~40). Based on the principle of mixed medicine, the present invention combines ferric chloride and 2-phosphonic acid butane-1,2,4-tricarboxylic acid into a lead inhibitor HQ-Pb according to a certain mass ratio, and through the synergistic effect between medicaments, HQ ‑Pb can strongly and selectively inhibit galena, but does not substantially affect the planktonic of chalcopyrite; 2‑phosphonic acid butane‑1,2,4‑tricarboxylic acid and chlorine Iron chemical is non-toxic and pollution-free. Effectively avoided the problem that the traditional galena inhibitor dichromate is highly toxic and extremely harmful to the environment and the human body; 2-phosphonic acid butane-1,2,4 in the combined inhibitor of the present invention ‑Tricarboxylic acid is an excellent water treatment agent with good water solubility and can complex with heavy metal ions in mineral processing wastewater, which can effectively reduce the difficulty and treatment cost of wastewater reuse.

The invention relates to a green environment-friendly leather tanning agent which is prepared from the following raw materials in parts by weight: 30-55 parts of naphthol, 12-26 parts of sulfuric acid, 1-2 parts of sodium sulfate, 1.5-2.6 parts of sodium carboxymethyl cellulose, 1.2-2 parts of ammonium persulfate, 4-10 parts of methylparaben, 7-12 parts of water-based lanolin, 6-13 parts of hydroxyethyl ethylenediamine, 1.3-2.4 parts of acrylic acid, 3-4 parts of myristic amide propyl hydroxypropyl sulphobetaine, 8-22 parts of sodium hydroxide, 3-6 parts of dichromate, 6-9 parts of silicon dioxide and 3-5 parts of glutaraldehyde. The green environment-friendly leather tanning agent has the advantages of high tanning speed, high tanning property and no irritating odor, can lighten and thin the leather and reduce the pollution, and conforms to the environment-friendly requirements.

The invention discloses a method for preparing medium chrome yellow from bichromate or chromate. The method for preparing medium chrome yellow from bichromate comprises the following steps: adding the bichromate and sulfate into a strong alkali solution, and preheating the bichromate, sulfate and the strong alkali solution; adding a lead nitrate solution; and sequentially adding sodium silicate and aluminum sulfate, and filtering the above obtained solution to obtain the medium chrome yellow. The method for preparing medium chrome yellow from chromate comprises the following steps: dissolving the chromate and sulfate in water, and preheating the chromate, sulfate and water; adding the lead nitrate solution; and sequentially adding sodium silicate and aluminum sulfate, and filtering the above obtained solution to obtain the medium chrome yellow. The preparation method has the advantages of simplicity, no generation of wastes or pollution, mild reaction conditions, great reduction of the synthesis cost, and great promotion and application potential in the chrome yellow preparation field.

The invention discloses a passivation solution for blades of a steam turbine. The passivation solution comprises the following components in percentage by weight: 10-14% of oxalic acid, 13-17% of tartaric acid, 2.5-3.5% of zinc nitrate, 3-5% of sodium bicarbonate, 3-5% of Mannich base, 2-4% of quinoline quaternary amine salt, 1-2% of urotropine, 0.5-1.5% of thiourea and the balance of water. The passivation solution contains no dichromate and nitrite and the original luster of parts are protected from being damaged after the parts are passivated by virtue of the passivation solution and the parts have excellent corrosion resistance.

The invention discloses a silver chromate / sulfur-doped carbon nitride Z-type photocatalyst. The silver chromate / sulfur-doped carbon nitride Z-type photocatalyst comprises carbon nitride, wherein sulfur is doped in the carbon nitride to form sulfur-doped carbon nitride, and the surface of the sulfur-doped carbon nitride is modified with silver chromate. A preparation method comprises the followingsteps of: uniformly mixing melamine, trithiocyanuric acid and ultrapure water, drying to obtain a mixture; calcining the mixture, grinding to obtain the sulfur-doped carbon nitride; mixing the sulfur-doped carbon nitride, silver-ion solution and dichromate solution to react, thus obtaining the silver chromate / sulfur-doped carbon nitride Z-type photocatalyst. The silver chromate / sulfur-doped carbonnitride Z-type photocatalyst disclosed by the invention has the advantages of strong light-absorbing capability, low photo-induced electron-hole recombination rate, good photocatalytic performance and good stability and the like, and is a novel photocatalytic material. The preparation method has the advantages of simple process, low cost and the like, is suitable for large-scale preparation and is beneficial to industrial production, and conditions can be controlled easily.

The invention relates to a method for preparing a chromium-doped ternary material. The method is characterized in that a chromium compound is Cr2O3, Cr(OH)3, Cr(NO3)3 or CrCl3, or a mixture of chromate or bichromate and a reducing agent and strong acid. According to the invention, nickel, cobalt, manganese and an ion-doped compound are mixed according to a mol ratio, through steps of wet grinding,ammoniacal liquor addition, lithium compound addition, aging, and drying, and a dried predecessor is prepared. The dried predecessor is placed in oxygen atmosphere, and the ternary material is prepared by a program heating method or a temperature gradual-heating method. The method has the advantages of low cost of raw material, wide raw material source, simple preparation technology, simple operation, and less time consuming. Compared with a coprecipitation method, the sewage discharged during a preparation process is obviously reduced, a prepared sample does not have a LiMn6 superlattice structure, and the prepared electrode material has the advantages of good consistency, uniform composition, and excellent discharge performance.

The invention provides a corrosive liquid and a preparation method of a chip mesa, and relates to the field of semiconductor chip preparation. The corrosive liquid comprises a solvent, dichromate andhaloid acid, wherein the dichromate and the haloid acid are dissolved in the solvent. By utilizing the corrosive liquid, the problems of non-uniform etching rate, rough etching surface and high etching cost caused by IPC dry etching of the existing chip can be solved, so that the etching rate is uniform, the etching cost is reduced, and the surface etching quality is improved.

The invention discloses a silver chromate / sulfur-doped carbon nitride Z-type photocatalyst. The silver chromate / sulfur-doped carbon nitride Z-type photocatalyst includes carbon nitride, and the carbon nitride is doped with sulfur element to form sulfur-doped Carbon nitride, sulfur-doped carbon nitride surface modified with silver chromate. The preparation method includes the following steps: mix melamine, thiocyanuric acid and ultrapure water evenly and dry to obtain a mixture; calcine and grind the mixture to obtain sulfur-doped carbon nitride; mix sulfur-doped carbon nitride and silver. The ionic solution and the dichromate solution are mixed and reacted to obtain a silver chromate / sulfur-doped carbon nitride Z-type photocatalyst. The silver chromate / sulfur-doped carbon nitride Z-type photocatalyst of the present invention has the advantages of strong light absorption ability, low photogenerated electron-hole recombination rate, good photocatalytic performance, and good stability. It is a new type of photocatalytic material. The preparation method has the advantages of simple process, easy control of conditions, low cost, etc., is suitable for large-scale preparation, and is beneficial to industrial production.

The present invention relates to a biphasic process for the epoxidation of an organic compound by organic compound by organic hydroperoxide. More particularly, the present invention relates to a biphasic process for the epoxidation of an organic compound by organic hydroperoxide to the corresponding epoxide, using chromate or dichromate anions as the catalyst in aqueous medium.

The invention discloses a chrome tanning waste liquid resourceful treatment method, and relates to the technical field of light industry environmental protection. According to the chrome tanning waste liquid resourceful treatment method, the chrome tanning waste liquid is creatively oxidized into dichromate under the acidic condition, trivalent chromium ions in the chrome tanning waste liquid can be efficiently and rapidly oxidized into hexavalent chromium ions, and the hexavalent chromium ions are applied to fur chrome mordant dyeing after excessive oxidizing agent removal, component detection and component adjustment; therefore, chromium, sodium chloride neutral salt and water in the chrome tanning waste liquid are efficiently recycled, and meanwhile, the recovery efficiency of hexavalent chromium in the chrome tanning waste liquid is improved.

The present invention relates to the development of an improved methodology for adsorption and subsequent reduction of hexavalent chromium aimed at the total removal of hexavalent chromium in water, which comprises, reacting dichromate solutions with natural ferrous-saponite clays at temperature 50 to 200° C. for the period of 1 to 3.0 hours.

The invention discloses a combined inhibitor for separating copper-lead sulphide ore and application of the combined inhibitor. The combined inhibitor comprises the following active components: ferricchloride and 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) in a mass ratio of (0.5-6): (2-40). According to a mixed medication principle, ferric chloride and PBTCA are combined according to thecertain mass ratio to form the lead inhibitor HQ-Pb; through the synergistic effect among reagents, the HQ-Pb can strongly and selectively inhibit galena, but basically does not influence the flotation of chalcopyrite; the PBTCA and ferric chloride in the combined inhibitor disclosed by the invention are non-toxic and pollution-free; the problem that a traditional galena inhibitor, namely dichromate is highly toxic and has great harm to the environment and human bodies is effectively avoided; and PBTCA in the combined inhibitor is an excellent water treatment agent, has good water solubility,can be complexed with heavy metal ions in beneficiation wastewater, and can effectively reduce the difficulty of wastewater reuse and treatment cost.

The full-automatic chemical oxygen demand analyzer comprises a digestion module, a condensation module, a lower liquid adding module, an upper liquid adding module, a stirring module and a titration module, and digestion, condensation, liquid adding, stirring and titration of a sample are automatically achieved. According to the full-automatic chemical oxygen demand analyzer based on the dichromate method, provided by the invention, full-automatic detection of CODCr is realized, the detection condition is stable, and the applicability is high.

The invention provides a preparation method and application of europium-doped calcium molybdate powder, the preparation method comprising the following steps: a, according to the chemical formula CaMoO 4 :Eu 3+ The stoichiometric ratio of Ca(NO 3 ) 2 Powder, Eu(NO 3 ) 3 aqueous solution and (NH 4 ) 6 Mo 7 o 24 Powder as raw material; b, Ca(NO 3 ) 2 powder and Eu(NO 3 ) 3 Put the aqueous solution in a mortar, add absolute ethanol and gum arabic powder, then grind to make the raw materials mix uniformly; c, add (NH 4 ) 6 Mo 7 o 24 Powder, continue to grind for 30~50min; d. Dry the mixture obtained in step c in an oven, then put it in a muffle furnace and roast at 600~620°C for 3~4h, and after cooling, you can get europium molybdenum doped Calcium acid powder. The invention also provides the application of the powder prepared by the above method in the quantitative detection of dichromate. The europium-doped calcium molybdate prepared by the invention has good selectivity to dichromate ion, simple and convenient detection process and high sensitivity.

The invention discloses a metal surface passivation solution which is characterized by comprising the following components in parts by mass: 1-3 parts of zinc nitrate, 1-4 parts of inorganic acid, 4-5 parts of water-soluble imidazoline, 2-3 parts of polycarboxylic acid, 0.1-0.3 part of phosphoryl carboxylic acid copolymer, 1-3 parts of ethylene diamine tetra (methylene sodium phosphate) and 100 parts of water. And 0.1-1 part of a defoaming agent is also included. Wherein the inorganic acid is selected from one or more of sulfuric acid, phosphoric acid and boric acid; the defoaming agent is selected from one or more of glycerol trihydroxy polyether, polyoxypropylene glycerol, polyoxyethylene oxypropylene glycerol, C7-C9 alcohol and a polyether modified silicone oil defoaming agent. The passivation solution has the following advantages that the passivation solution does not contain dichromate and nitrite, and a metal material adopting the passivation solution is excellent in corrosion resistance and adhesive force after being passivated.

The invention provides a homogeneous oxidation synthesis method of isosulfan blue. The homogeneous oxidation synthesis method comprises the steps that when acid blue is used as a raw material, tetravalent cerium salt is used as an oxidizing agent, water or a mixed solvent of water and other solvents is used as a solvent, the acid blue is oxidized in the presence of acid, thus preparing the isosulfan blue; The method is carried out at the temperature of -10 to10 DEG C, the deethylation impurity rate is less than 0.15%, and the use of expensive oxidant silver oxide and dangerous reagents permanganate and dichromate is avoided, so that the method is greener and more environment-friendly.

The invention relates to a chromium slag treatment process, which comprises the following steps: carrying out primary extraction, secondary extraction, tertiary extraction and quaternary extraction on chromium slag, and then enabling the filtrate of each stage of extraction to enter the next batch of chromium slag treatment process for reuse, wherein most chromium is dissociated from the chromium slag in an aqueous solution, so that the chromium content in the chromium slag is reduced; and after multi-stage water extraction, cooling filtrate to room temperature to separate out dichromate, filtering, adding sodium hydrogen sulfite for reduction, precipitating chromium hydroxide, and continuously extracting the next batch of chromium slag by taking liquid after solid-liquid separation as circulating water. According to the method, water is used as a solvent, multi-stage extraction is carried out, filtrate can be reused in batches, the water consumption is reduced, the detoxified chromium slag can be buried and used as a road repairing material for manufacturing building materials, dichromate and chromium hydroxide can be reused as industrial raw materials.

The invention relates to a method for cleaning the process gas in soldering installation and solder suction systems, in particular for reducing the abietic acid in the process gas, wherein the process gas to be cleaned is conducted through a cleaning system which contains one or more of the following compounds (cleaning compounds):a) carboxylic acids with reducing properties, namely oxalic acid, formic acid, citric acid and / or ascorbic acid:b) metal compounds of higher oxidation states, namely manganates, permanganates, chromates and / or dichromates;c) alcohols which can be convened into the carboxylic acids mentioned in a) by means of oxidation;d) basic lime compounds.

The invention discloses a synthetic method for preparing a compound containing diphenyl sulfoxide through electrochemical catalytic oxidation, which is characterized in that the synthetic reaction formula is as follows: R1 and R2 are hydrogen, alkyl or alkyl; the catalyst is a compound composed of a metal catalyst and a ligand thereof; the oxidizing agent comprises peroxide, chlorate, dichromate, inorganic acid and a mixture of one or two of oxygen, ozone and air; the reaction is carried out in an organic solvent. The method is high in conversion rate and low in cost.

The invention discloses an ash removal agent for deplating of a zinc-nickel alloy electroplated layer and a using method. The ash removal agent is prepared from the following components of an agent A, an agent B and a solvent, wherein the agent A is prepared from the following components of 40-80g / L of carbonate and 100-140g / L of alkali liquor; the agent B is prepared from the following components of 20-30g / L of a sodium salt removing agent and 30-45g / L of dichromate; the carbonate is sodium carbonate and / or potassium carbonate; the alkali liquor is sodium hydroxide and / or potassium hydroxide; the sodium salt removing agent is sodium chlorate or sodium hypochlorite; and the dichromate is sodium dichromate or potassium dichromate. The using method comprises the following steps of, (1) soaking a workpiece in a tank by using the ash removal agent through the step (1)- (3). The ash removal agent is used for treating a replating workpiece to remove black oxidized ash generated by deplating of the replating workpiece, so that the surface of the replating workpiece is completely consistent with the surface of a previous incoming workpiece in appearance, a base body is not damaged, and replating electroplating can be directly carried out.