Sodium dichromate

About: Sodium dichromate is a research topic. Over the lifetime, 421 publications have been published within this topic receiving 6202 citations. The topic is also known as: Disodium salt & sodium bichromate.

Method for removing chlorine of sodium dichromate by electrolysis

Abstract: The invention discloses a method for removing chlorine of sodium dichromate by electrolysis. The method includes the following steps: an anolyte and a catholyte are heated for raising temperature; theanolyte is a sodium dichromate solution or a sodium chromate alkaline solution; the catholyte is a sodium hydroxide solution or a sodium chromate solution; an electrolytic cell circulation pump is turned on, the anolyte is pumped into an anode cavity in an electrolytic cell through an anode pump, the catholyte is pumped into a cathode cavity in the electrolytic cell through a cathode pump, and direct current is introduced to an anode plate of the anode cavity and a cathode plate of the cathode cavity for performing electrolysis; wherein the electrolytic cell is a diaphragm electrolytic cell;and a separation diaphragm is disposed between the cathode cavity and the anode cavity of the diaphragm electrolytic cell. The method can acidify the sodium dichromate solution while the chlorine is removed by the electrolysis, the amount of sulfuric acid acidification added during a production process of the sodium dichromate can be reduced to some extent, new impurities are not introduced in a whole process, the content of chloride ions is reduced, the quality of a product is improved, and during a process, the quantity of output of by-product mirabilite in production of the sodium dichromate is reduced.

Synthetic process of isatin

Abstract: The invention discloses a synthetic process of isatin, comprising the steps of S1, adding indigo, water and copper dichloride into a reactor, heating a reaction system to 60-90 DEG C, stirring to allow dissolving, introducing pure oxygen slowly, and allowing to react at 60-90 DEG C for 3-6 h; S2, filtering when the temperature is 60-90 DEG C, washing filter cake with water once to three times, anddrying at 80-100 DEG C to obtain isatin. Water is used as a solvent to the reaction system herein, using massive sulfuric acid is not required, and the water as the solvent is reusable; oxygen is used as a catalyst and is nontoxic and clean as compared to sodium dichromate, and sodium dichromate is of heavy metal type and explosive type and is highly dangerous to the environment, while oxygen isnontoxic and harmless; indigo is used as the raw material which is low in price, and industrial production of indigo helps greatly reduce the production cost; the yield of the synthetic process reaches 85% which is evidently higher than the prior yield which is 70-80%.

A method of disposing of effluents containing formaldehyde or formaldehyde precursors such as hexamine

Abstract: In a method of treating effluents containing formaldehyde and/or precursors thereof, a compound containing hexavalent chromium, particularly sodium dichromate, is added to the effluents in an acid environment to give a solution which contains trivalent chromium ions and products of the oxidation of all of the formaldehyde and/or precursors thereof, and which can be used for tanning hides.

Vehicle exhaust pipe

Abstract: The invention discloses a vehicle exhaust pipe. The vehicle exhaust pipe is produced by the following raw materials: steel products, aluminum products, copper products, linear alkyl benzene sulfonate, octaphenyl polyoxyethyiene, glycol, phosphoric acid, sodium dichromate, zinc oxide, micron graphite fibers, and micron potassium feldspar. The linear alkyl benzene sulfonate, the octaphenyl polyoxyethyiene, the glycol, the phosphoric acid, the sodium dichromate, the graphite fibers and the potassium feldspar are added on the basis of traditional materials of the vehicle exhaust pipe for improvement to improve the rust resistance, wherein the linear alkyl benzene sulfonate, the octaphenyl polyoxyethyiene, the glycol, the phosphoric acid, the sodium dichromate and the potassium feldspar not only can effectively promote a permeation effect between the raw materials and the steel products, the aluminum products and the copper products, but also can form a layer of protective film on a product to achieve a rust resisting effect; and in particular, the potassium feldspar can effectively promote mutual permeation among all the raw materials to reduce the gap of the vehicle exhaust pipe so as to further improve the rust resistance.

Desulfurizer for coal washing

Abstract: The invention belongs to the technical field of desulfurizers, and particularly relates to a desulfurizer for desulfurizing of coal washing, which aims at providing a desulfurizer with the purposes ofeffectively complexing and cleaning inorganic sulfur in the coal and generating the sulfides and other harmful matters into harmful matters via chemical reaction. The desulfurizer is prepared from the following raw materials in parts by weight according: 10 to 25 parts of sodium hypochlorite, 12 to 20 parts of ammonium persulfate, 5 to 12 parts of sodium glycollate, 6 to 10 parts of sodium acetate, 7 to 12 parts of potassium citrate, 6 to 8 parts of sodium gluconate, 5 to 9 parts of ethylenediamine tetraacetic acid, 1 to 12 parts of ferric sulfate, 10 to 15 parts of triethanolamine, 3 to 9 parts of sodium dichromate, 3 to 5 parts of aluminum ferric chloride, 1 to 2 parts of urea, 3 to 5 parts of sodium bicarbonate, 0.1 to 0.5 part of octadecyl trimethyl ammonium chloride, 0.5 to 0.8 partof sodium dodecyl benzene sulfonate, 0.2 to 0.4 part of a dispersant, and 50 to 90 parts of water.